diff --git a/core/composer.json b/core/composer.json
index 53ab8fa..862b5a3 100644
--- a/core/composer.json
+++ b/core/composer.json
@@ -94,6 +94,7 @@
         "drupal/editor": "self.version",
         "drupal/entity_reference": "self.version",
         "drupal/field": "self.version",
+        "drupal/field_layout": "self.version",
         "drupal/field_ui": "self.version",
         "drupal/file": "self.version",
         "drupal/filter": "self.version",
diff --git a/core/modules/field_layout/config/schema/field_layout.schema.yml b/core/modules/field_layout/config/schema/field_layout.schema.yml
new file mode 100644
index 0000000..3460b05
--- /dev/null
+++ b/core/modules/field_layout/config/schema/field_layout.schema.yml
@@ -0,0 +1,13 @@
+core.entity_view_display.*.*.*.third_party.field_layout:
+  type: field_layout.third_party_settings
+
+core.entity_form_display.*.*.*.third_party.field_layout:
+  type: field_layout.third_party_settings
+
+field_layout.third_party_settings:
+  type: mapping
+  label: 'Per-view mode field layout settings'
+  mapping:
+    layout:
+      type: string
+      label: 'Layout'
diff --git a/core/modules/field_layout/field_layout.info.yml b/core/modules/field_layout/field_layout.info.yml
new file mode 100644
index 0000000..62f225a
--- /dev/null
+++ b/core/modules/field_layout/field_layout.info.yml
@@ -0,0 +1,6 @@
+name: 'Field Layout'
+type: module
+description: 'Adds layout capabilities to the Field UI.'
+package: Core (Experimental)
+version: VERSION
+core: 8.x
diff --git a/core/modules/field_layout/field_layout.install b/core/modules/field_layout/field_layout.install
new file mode 100644
index 0000000..456054e
--- /dev/null
+++ b/core/modules/field_layout/field_layout.install
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * @file
+ * Contains install and update functions for Field Layout.
+ */
+
+use Drupal\Core\Cache\Cache;
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\Core\Entity\EntityInterface;
+
+/**
+ * Implements hook_install().
+ */
+function field_layout_install() {
+  // Save each entity display in order to trigger field_layout_entity_presave().
+  $entity_save = function (EntityInterface $entity) {
+    $entity->save();
+  };
+  array_map($entity_save, EntityViewDisplay::loadMultiple());
+  array_map($entity_save, EntityFormDisplay::loadMultiple());
+
+  // Invalidate the render cache since all content will now have a layout.
+  Cache::invalidateTags(['rendered']);
+}
diff --git a/core/modules/field_layout/field_layout.libraries.yml b/core/modules/field_layout/field_layout.libraries.yml
new file mode 100644
index 0000000..d87df5e
--- /dev/null
+++ b/core/modules/field_layout/field_layout.libraries.yml
@@ -0,0 +1,5 @@
+drupal.field_layout.twocol:
+  version: VERSION
+  css:
+    layout:
+      layouts/twocol/twocol.layout.css: {}
diff --git a/core/modules/field_layout/field_layout.module b/core/modules/field_layout/field_layout.module
new file mode 100644
index 0000000..0ab3305
--- /dev/null
+++ b/core/modules/field_layout/field_layout.module
@@ -0,0 +1,111 @@
+<?php
+
+/**
+ * @file
+ * Provides hook implementations for Field Layout.
+ */
+
+use Drupal\Core\Entity\ContentEntityFormInterface;
+use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+use Drupal\field_layout\Entity\FieldLayoutEntityFormDisplay;
+use Drupal\field_layout\Entity\FieldLayoutEntityViewDisplay;
+use Drupal\field_layout\FieldLayoutBuilder;
+use Drupal\field_layout\Form\FieldLayoutEntityFormDisplayEditForm;
+use Drupal\field_layout\Form\FieldLayoutEntityViewDisplayEditForm;
+
+/**
+ * Implements hook_help().
+ */
+function field_layout_help($route_name, RouteMatchInterface $route_match) {
+  switch ($route_name) {
+    case 'help.page.field_layout':
+      $output = '<h3>' . t('About') . '</h3>';
+      $output .= '<p>' . t('The Field Layout module allows you to arrange fields into regions for content forms and displays.') . '</p>';
+      $output .= '<p>' . t('For more information, see the <a href=":field-layout-documentation">online documentation for the Field Layout module</a>.', [':field-layout-documentation' => 'https://www.drupal.org/documentation/modules/@todo_once_module_name_is_decided_upon']) . '</p>';
+      return $output;
+  }
+}
+
+/**
+ * Implements hook_entity_type_alter().
+ */
+function field_layout_entity_type_alter(array &$entity_types) {
+  /** @var $entity_types \Drupal\Core\Entity\EntityTypeInterface[] */
+  $entity_types['entity_view_display']->setClass(FieldLayoutEntityViewDisplay::class);
+  $entity_types['entity_form_display']->setClass(FieldLayoutEntityFormDisplay::class);
+
+  // The form classes are only needed when Field UI is installed.
+  if (\Drupal::moduleHandler()->moduleExists('field_ui')) {
+    $entity_types['entity_view_display']->setFormClass('edit', FieldLayoutEntityViewDisplayEditForm::class);
+    $entity_types['entity_form_display']->setFormClass('edit', FieldLayoutEntityFormDisplayEditForm::class);
+  }
+}
+
+/**
+ * Implements hook_ENTITY_TYPE_presave() for entity_form_display entities.
+ */
+function field_layout_entity_form_display_presave(EntityInterface $entity) {
+  _field_layout_entity_display_presave($entity);
+}
+
+/**
+ * Implements hook_ENTITY_TYPE_presave() for entity_view_display entities.
+ */
+function field_layout_entity_view_display_presave(EntityInterface $entity) {
+  _field_layout_entity_display_presave($entity);
+}
+
+/**
+ * Ensure there is a layout set on a display entity.
+ *
+ * @param \Drupal\Core\Entity\EntityInterface $entity
+ *   The entity object.
+ */
+function _field_layout_entity_display_presave(EntityInterface $entity) {
+  if ($entity instanceof EntityDisplayWithLayoutInterface && !$entity->getLayoutId()) {
+    $entity->setLayoutId('onecol');
+  }
+}
+
+/**
+ * Implements hook_entity_view_alter().
+ */
+function field_layout_entity_view_alter(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display) {
+  if ($display instanceof EntityDisplayWithLayoutInterface) {
+    \Drupal::classResolver()->getInstanceFromDefinition(FieldLayoutBuilder::class)
+      ->build($build, $display, 'view');
+  }
+}
+
+/**
+ * Implements hook_form_alter().
+ */
+function field_layout_form_alter(&$form, FormStateInterface $form_state, $form_id) {
+  $form_object = $form_state->getFormObject();
+  if ($form_object instanceof ContentEntityFormInterface && $display = $form_object->getFormDisplay($form_state)) {
+    if ($display instanceof EntityDisplayWithLayoutInterface) {
+      \Drupal::classResolver()->getInstanceFromDefinition(FieldLayoutBuilder::class)
+        ->build($form, $display, 'form');
+    }
+  }
+}
+
+/**
+ * Implements hook_theme().
+ */
+function field_layout_theme($existing, $type, $theme, $path) {
+  $hooks = [];
+  $layout_definitions = \Drupal::service('field_layout.layout_repository')->getDefinitions();
+  foreach ($layout_definitions as $layout_definition) {
+    $hooks[$layout_definition['theme']] = [
+      'render element' => 'content',
+      'template' => $layout_definition['template'],
+      'path' => $layout_definition['path'],
+    ];
+  }
+  return $hooks;
+}
diff --git a/core/modules/field_layout/field_layout.services.yml b/core/modules/field_layout/field_layout.services.yml
new file mode 100644
index 0000000..95c7162
--- /dev/null
+++ b/core/modules/field_layout/field_layout.services.yml
@@ -0,0 +1,4 @@
+services:
+  field_layout.layout_repository:
+    class: Drupal\field_layout\LayoutRepository
+    arguments: ['@module_handler', '@theme_handler', '@string_translation']
diff --git a/core/modules/field_layout/layouts/onecol/field-layout--onecol.html.twig b/core/modules/field_layout/layouts/onecol/field-layout--onecol.html.twig
new file mode 100644
index 0000000..cce4893
--- /dev/null
+++ b/core/modules/field_layout/layouts/onecol/field-layout--onecol.html.twig
@@ -0,0 +1,24 @@
+{#
+/**
+ * @file
+ * Default theme implementation to display a one column layout.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'field-layout--onecol',
+]
+%}
+{% if content %}
+<div{{ attributes.addClass(classes) }}>
+  <div class="field-layout-region field-layout-region--content">
+    {{ content }}
+  </div>
+</div>
+{% endif %}
diff --git a/core/modules/field_layout/layouts/twocol/field-layout--twocol.html.twig b/core/modules/field_layout/layouts/twocol/field-layout--twocol.html.twig
new file mode 100644
index 0000000..4dffc01
--- /dev/null
+++ b/core/modules/field_layout/layouts/twocol/field-layout--twocol.html.twig
@@ -0,0 +1,28 @@
+{#
+/**
+ * @file
+ * Default theme implementation to display a two column layout.
+ *
+ * Available variables:
+ * - content: The content for this layout.
+ * - attributes: HTML attributes for the layout <div>.
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+set classes = [
+'field-layout--twocol',
+]
+%}
+{% if content %}
+  <div{{ attributes.addClass(classes) }}>
+    <div class="field-layout-region field-layout-region--left">
+      {{ content.left }}
+    </div>
+
+    <div class="field-layout-region field-layout-region--right">
+      {{ content.right }}
+    </div>
+  </div>
+{% endif %}
diff --git a/core/modules/field_layout/layouts/twocol/twocol.layout.css b/core/modules/field_layout/layouts/twocol/twocol.layout.css
new file mode 100644
index 0000000..8e2f623
--- /dev/null
+++ b/core/modules/field_layout/layouts/twocol/twocol.layout.css
@@ -0,0 +1,14 @@
+.field-layout--twocol {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: space-between;
+}
+.field-layout--twocol > .field-layout-region {
+  flex: 0 1 50%;
+  max-width: 50%;
+}
+
+.field-layout--twocol > .field-layout-region--left {
+  max-width: calc(50% - 10px);
+  margin-right: 10px;
+}
diff --git a/core/modules/field_layout/src/Display/EntityDisplayWithLayoutInterface.php b/core/modules/field_layout/src/Display/EntityDisplayWithLayoutInterface.php
new file mode 100644
index 0000000..f98087f
--- /dev/null
+++ b/core/modules/field_layout/src/Display/EntityDisplayWithLayoutInterface.php
@@ -0,0 +1,38 @@
+<?php
+
+namespace Drupal\field_layout\Display;
+
+use Drupal\Core\Entity\Display\EntityDisplayInterface;
+
+/**
+ * Provides a common interface for entity displays that have layout.
+ */
+interface EntityDisplayWithLayoutInterface extends EntityDisplayInterface {
+
+  /**
+   * Gets the default region.
+   *
+   * @return string
+   *   The default region for this display.
+   */
+  public function getDefaultRegion();
+
+  /**
+   * Gets the layout ID for this display.
+   *
+   * @return string
+   *   The layout ID.
+   */
+  public function getLayoutId();
+
+  /**
+   * Sets the layout ID for this display.
+   *
+   * @param string|null $layout_id
+   *   Either a valid layout ID, or NULL to remove the layout setting.
+   *
+   * @return $this
+   */
+  public function setLayoutId($layout_id);
+
+}
diff --git a/core/modules/field_layout/src/Entity/FieldLayoutEntityDisplayTrait.php b/core/modules/field_layout/src/Entity/FieldLayoutEntityDisplayTrait.php
new file mode 100644
index 0000000..567e8b4
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityDisplayTrait.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Drupal\field_layout\Entity;
+
+/**
+ * Provides shared code for entity displays.
+ */
+trait FieldLayoutEntityDisplayTrait {
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::getLayoutId().
+   */
+  public function getLayoutId() {
+    return $this->getThirdPartySetting('field_layout', 'layout');
+  }
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::setLayoutId().
+   */
+  public function setLayoutId($layout_id) {
+    $this->setThirdPartySetting('field_layout', 'layout', $layout_id);
+    return $this;
+  }
+
+}
diff --git a/core/modules/field_layout/src/Entity/FieldLayoutEntityFormDisplay.php b/core/modules/field_layout/src/Entity/FieldLayoutEntityFormDisplay.php
new file mode 100644
index 0000000..2dfa838
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityFormDisplay.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\field_layout\Entity;
+
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+
+/**
+ * Provides an entity form display entity that has layout.
+ */
+class FieldLayoutEntityFormDisplay extends EntityFormDisplay implements EntityDisplayWithLayoutInterface {
+
+  use FieldLayoutEntityDisplayTrait;
+
+  /**
+   * {@inheritdoc}
+   *
+   * This cannot be provided by the trait due to https://bugs.php.net/bug.php?id=71414
+   * which is fixed in PHP 7.0.6.
+   */
+  public function getDefaultRegion() {
+    $layout_definition = \Drupal::service('field_layout.layout_repository')->getLayout($this->getLayoutId() ?: 'onecol');
+    return isset($layout_definition['default_region']) ? $layout_definition['default_region'] : key($layout_definition['regions']);
+  }
+
+}
diff --git a/core/modules/field_layout/src/Entity/FieldLayoutEntityViewDisplay.php b/core/modules/field_layout/src/Entity/FieldLayoutEntityViewDisplay.php
new file mode 100644
index 0000000..e34fc57
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityViewDisplay.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace Drupal\field_layout\Entity;
+
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+
+/**
+ * Provides an entity view display entity that has layout.
+ */
+class FieldLayoutEntityViewDisplay extends EntityViewDisplay implements EntityDisplayWithLayoutInterface {
+
+  use FieldLayoutEntityDisplayTrait;
+
+  /**
+   * {@inheritdoc}
+   *
+   * This cannot be provided by the trait due to https://bugs.php.net/bug.php?id=71414
+   * which is fixed in PHP 7.0.6.
+   */
+  public function getDefaultRegion() {
+    $layout_definition = \Drupal::service('field_layout.layout_repository')->getLayout($this->getLayoutId() ?: 'onecol');
+    return isset($layout_definition['default_region']) ? $layout_definition['default_region'] : key($layout_definition['regions']);
+  }
+
+}
diff --git a/core/modules/field_layout/src/FieldLayoutBuilder.php b/core/modules/field_layout/src/FieldLayoutBuilder.php
new file mode 100644
index 0000000..8b35c74
--- /dev/null
+++ b/core/modules/field_layout/src/FieldLayoutBuilder.php
@@ -0,0 +1,128 @@
+<?php
+
+namespace Drupal\field_layout;
+
+use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
+use Drupal\Core\Entity\EntityFieldManagerInterface;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Builds a field layout.
+ */
+class FieldLayoutBuilder implements ContainerInjectionInterface {
+
+  /**
+   * The layout repository.
+   *
+   * @var \Drupal\field_layout\LayoutRepositoryInterface
+   */
+  protected $layoutRepository;
+
+  /**
+   * The entity field manager.
+   *
+   * @var \Drupal\Core\Entity\EntityFieldManagerInterface
+   */
+  protected $entityFieldManager;
+
+  /**
+   * FieldLayoutBuilder constructor.
+   *
+   * @param \Drupal\field_layout\LayoutRepositoryInterface $layout_repository
+   * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
+   */
+  public function __construct(LayoutRepositoryInterface $layout_repository, EntityFieldManagerInterface $entity_field_manager) {
+    $this->layoutRepository = $layout_repository;
+    $this->entityFieldManager = $entity_field_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('field_layout.layout_repository'),
+      $container->get('entity_field.manager')
+    );
+  }
+
+  /**
+   * Applies the layout to an entity build.
+   *
+   * @param array $build
+   *   A renderable array representing the entity content or form.
+   * @param \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface $display
+   *   The entity display holding the display options configured for the entity
+   *   components.
+   * @param string $display_context
+   *   The display context, either 'form' or 'view'. If in a 'form' context, an
+   *   alternate method will be used to render fields in their regions.
+   */
+  public function build(array &$build, EntityDisplayWithLayoutInterface $display, $display_context) {
+    $layout_definition = $this->layoutRepository->getLayout($display->getLayoutId());
+    if ($layout_definition && $fields = $this->getFields($build, $display, $display_context)) {
+      // Wrap the regions in a layout element.
+      $build['field_layout']['#theme'] = $layout_definition['theme'];
+      if (isset($layout_definition['library'])) {
+        $build['field_layout']['#attached']['library'][] = $layout_definition['library'];
+      }
+
+      // Add the regions to the $build in the correct order.
+      foreach ($layout_definition['regions'] as $region => $region_info) {
+        $build['field_layout'][$region] = [];
+        if ($display_context === 'form') {
+          $build['field_layout'][$region]['#process'][] = '\Drupal\Core\Render\Element\RenderElement::processGroup';
+          $build['field_layout'][$region]['#pre_render'][] = '\Drupal\Core\Render\Element\RenderElement::preRenderGroup';
+        }
+      }
+
+      foreach ($fields as $name => $field) {
+        // If this is a form, #group can be used to relocate the fields. This
+        // avoids breaking hook_form_alter() implementations by not actually
+        // moving the field in the form structure.
+        if ($display_context === 'form') {
+          $build[$name]['#group'] = $field['region'];
+        }
+        // Otherwise, move the field from the top-level of $build into a
+        // region-specific section.
+        else {
+          $build['field_layout'][$field['region']][$name] = $build[$name];
+          unset($build[$name]);
+        }
+      }
+    }
+  }
+
+  /**
+   * Gets the fields that need to be processed.
+   *
+   * @param array $build
+   *   A renderable array representing the entity content or form.
+   * @param \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface $display
+   *   The entity display holding the display options configured for the entity
+   *   components.
+   * @param string $display_context
+   *   The display context, either 'form' or 'view'.
+   *
+   * @return array
+   *   An array of configurable fields present in the build.
+   */
+  protected function getFields(array $build, EntityDisplayWithLayoutInterface $display, $display_context) {
+    $components = $display->getComponents();
+
+    $field_definitions = $this->entityFieldManager->getFieldDefinitions($display->getTargetEntityTypeId(), $display->getTargetBundle());
+    $non_configurable_fields = array_filter($field_definitions, function (FieldDefinitionInterface $field_definition) use ($display_context) {
+      return !$field_definition->isDisplayConfigurable($display_context);
+    });
+    // Remove non-configurable fields.
+    $components = array_diff_key($components, $non_configurable_fields);
+
+    // Only include fields present in the build.
+    $components = array_intersect_key($components, $build);
+
+    return $components;
+  }
+
+}
diff --git a/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
new file mode 100644
index 0000000..46c90d3
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
@@ -0,0 +1,115 @@
+<?php
+
+namespace Drupal\field_layout\Form;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+
+/**
+ * Provides shared code for entity display forms.
+ */
+trait FieldLayoutEntityDisplayFormTrait {
+
+  /**
+   * The field layout repository.
+   *
+   * @var \Drupal\field_layout\LayoutRepositoryInterface
+   */
+  protected $fieldLayoutRepository;
+
+  /**
+   * Overrides \Drupal\field_ui\Form\EntityDisplayFormBase::getRegions().
+   */
+  public function getRegions() {
+    $regions = [];
+
+    $layout = $this->fieldLayoutRepository->getLayout($this->getEntity()->getLayoutId() ?: 'onecol');
+    foreach ($layout['regions'] as $name => $region) {
+      $regions[$name] = [
+        'title' => $region['label'],
+        'message' => $this->t('No field is displayed.')
+      ];
+    }
+
+    $regions['hidden'] = [
+      'title' => $this->t('Disabled', [], ['context' => 'Plural']),
+      'message' => $this->t('No field is hidden.')
+    ];
+
+    return $regions;
+  }
+
+  /**
+   * Adds the field layout section to the form.
+   *
+   * @param array $form
+   *   An associative array containing the structure of the form.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   *
+   * @return array
+   */
+  protected function addFieldLayout(array $form, FormStateInterface $form_state) {
+    $form['#entity_builders'][] = [static::class, 'updateFieldLayout'];
+
+    $form['field_layouts'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Layout settings'),
+    ];
+    $layout_options = [];
+    foreach ($this->fieldLayoutRepository->getGroupedDefinitions() as $category => $layouts) {
+      foreach ($layouts as $name => $layout) {
+        $layout_options[$category][$name] = $layout['label'];
+      }
+    }
+    $form['field_layouts']['field_layout'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Select a layout'),
+      '#options' => $layout_options,
+      '#default_value' => $this->getEntity()->getLayoutId() ?: 'onecol',
+    ];
+
+    return $form;
+  }
+
+  /**
+   * An #entity_builder callback to update the Field Layout settings.
+   *
+   * @param string $entity_type_id
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   * @param array $form
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   */
+  public static function updateFieldLayout($entity_type_id, EntityInterface $entity, &$form, FormStateInterface $form_state) {
+    if ($form_state->isSubmitted() && $entity instanceof EntityDisplayWithLayoutInterface) {
+      $old_layout = $entity->getLayoutId();
+      $new_layout = $form_state->getValue('field_layout');
+      $entity->setLayoutId($new_layout);
+      // If the layout is changing, reset all fields.
+      if ($new_layout !== $old_layout) {
+        // @todo Devise a mechanism for mapping old regions to new ones in
+        //   https://www.drupal.org/node/2796877.
+        $new_region = $entity->getDefaultRegion();
+        foreach ($form_state->getValue('fields') as $field_name => $values) {
+          if (($component = $entity->getComponent($field_name)) && $new_region !== 'hidden') {
+            $component['region'] = $new_region;
+            $entity->setComponent($field_name, $component);
+          }
+          else {
+            $entity->removeComponent($field_name);
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * Gets the form entity.
+   *
+   * @return \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface
+   *   The current form entity.
+   */
+  abstract public function getEntity();
+
+}
diff --git a/core/modules/field_layout/src/Form/FieldLayoutEntityFormDisplayEditForm.php b/core/modules/field_layout/src/Form/FieldLayoutEntityFormDisplayEditForm.php
new file mode 100644
index 0000000..d57912e
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityFormDisplayEditForm.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Drupal\field_layout\Form;
+
+use Drupal\Component\Plugin\PluginManagerBase;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\Field\FieldTypePluginManagerInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\field_layout\LayoutRepositoryInterface;
+use Drupal\field_ui\Form\EntityFormDisplayEditForm;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Edit form for the EntityFormDisplay entity type.
+ */
+class FieldLayoutEntityFormDisplayEditForm extends EntityFormDisplayEditForm {
+
+  use FieldLayoutEntityDisplayFormTrait;
+
+  /**
+   * FieldLayoutEntityFormDisplayEditForm constructor.
+   *
+   * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
+   *   The field type manager.
+   * @param \Drupal\Component\Plugin\PluginManagerBase $plugin_manager
+   *   The widget plugin manager.
+   * @param \Drupal\field_layout\LayoutRepositoryInterface $field_layout_repository
+   *   The field layout repository.
+   */
+  public function __construct(FieldTypePluginManagerInterface $field_type_manager, PluginManagerBase $plugin_manager, LayoutRepositoryInterface $field_layout_repository) {
+    parent::__construct($field_type_manager, $plugin_manager);
+    $this->fieldLayoutRepository = $field_layout_repository;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.field.field_type'),
+      $container->get('plugin.manager.field.widget'),
+      $container->get('field_layout.layout_repository')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function form(array $form, FormStateInterface $form_state) {
+    $form = parent::form($form, $form_state);
+    return $this->addFieldLayout($form, $form_state);
+  }
+
+}
diff --git a/core/modules/field_layout/src/Form/FieldLayoutEntityViewDisplayEditForm.php b/core/modules/field_layout/src/Form/FieldLayoutEntityViewDisplayEditForm.php
new file mode 100644
index 0000000..5c9f26f
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityViewDisplayEditForm.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace Drupal\field_layout\Form;
+
+use Drupal\Component\Plugin\PluginManagerBase;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\Field\FieldTypePluginManagerInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\field_layout\LayoutRepositoryInterface;
+use Drupal\field_ui\Form\EntityViewDisplayEditForm;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Edit form for the EntityViewDisplay entity type.
+ */
+class FieldLayoutEntityViewDisplayEditForm extends EntityViewDisplayEditForm {
+
+  use FieldLayoutEntityDisplayFormTrait;
+
+  /**
+   * FieldLayoutEntityViewDisplayEditForm constructor.
+   *
+   * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
+   *   The field type manager.
+   * @param \Drupal\Component\Plugin\PluginManagerBase $plugin_manager
+   *   The formatter plugin manager.
+   * @param \Drupal\field_layout\LayoutRepositoryInterface $field_layout_repository
+   *   The field layout repository.
+   */
+  public function __construct(FieldTypePluginManagerInterface $field_type_manager, PluginManagerBase $plugin_manager, LayoutRepositoryInterface $field_layout_repository) {
+    parent::__construct($field_type_manager, $plugin_manager);
+    $this->fieldLayoutRepository = $field_layout_repository;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.field.field_type'),
+      $container->get('plugin.manager.field.formatter'),
+      $container->get('field_layout.layout_repository')
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function form(array $form, FormStateInterface $form_state) {
+    $form = parent::form($form, $form_state);
+    return $this->addFieldLayout($form, $form_state);
+  }
+
+}
diff --git a/core/modules/field_layout/src/LayoutRepository.php b/core/modules/field_layout/src/LayoutRepository.php
new file mode 100644
index 0000000..02a21c8
--- /dev/null
+++ b/core/modules/field_layout/src/LayoutRepository.php
@@ -0,0 +1,142 @@
+<?php
+
+namespace Drupal\field_layout;
+
+use Drupal\Component\Plugin\Discovery\DiscoveryTrait;
+use Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Extension\ThemeHandlerInterface;
+use Drupal\Core\Plugin\CategorizingPluginManagerTrait;
+use Drupal\Core\StringTranslation\TranslationInterface;
+
+/**
+ * Provides a repository for field layouts.
+ */
+class LayoutRepository implements LayoutRepositoryInterface {
+
+  /**
+   * The module handler.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * The theme handler.
+   *
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
+  use DiscoveryTrait;
+  use CategorizingPluginManagerTrait {
+    getModuleHandler as protected;
+    getCategories as protected;
+    getSortedDefinitions as protected;
+  }
+
+  /**
+   * LayoutRepository constructor.
+   *
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   The module handler.
+   * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
+   *   The theme handler.
+   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
+   *   The string translation service.
+   */
+  public function __construct(ModuleHandlerInterface $module_handler, ThemeHandlerInterface $theme_handler, TranslationInterface $string_translation) {
+    $this->moduleHandler = $module_handler;
+    $this->themeHandler = $theme_handler;
+    $this->stringTranslation = $string_translation;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getDefinitions() {
+    // @todo Replace with layout_plugin in https://www.drupal.org/node/2296423.
+    $layouts = [
+      'onecol' => [
+        'label' => $this->t('One column'),
+        'theme' => 'field_layout__onecol',
+        'path' => 'layouts/onecol',
+        'provider' => 'field_layout',
+        'category' => $this->t('Columns: 1'),
+        'default_region' => 'content',
+        'regions' => [
+          'content' => [
+            'label' => $this->t('Content'),
+          ],
+        ],
+      ],
+      'twocol' => [
+        'label' => $this->t('Two column'),
+        'library' => 'field_layout/drupal.field_layout.twocol',
+        'theme' => 'field_layout__twocol',
+        'path' => 'layouts/twocol',
+        'provider' => 'field_layout',
+        'category' => $this->t('Columns: 2'),
+        'default_region' => 'left',
+        'regions' => [
+          'left' => [
+            'label' => $this->t('Left'),
+          ],
+          'right' => [
+            'label' => $this->t('Right'),
+          ],
+        ],
+      ],
+    ];
+    foreach ($layouts as $layout_id => &$layout) {
+      $this->processDefinition($layout, $layout_id);
+    }
+    return $layouts;
+  }
+
+  /**
+   * Performs extra processing on layout definitions.
+   */
+  protected function processDefinition(&$definition, $plugin_id) {
+    $definition['layout'] = $plugin_id;
+
+    // Add the module or theme path to the 'path'.
+    if ($this->moduleHandler->moduleExists($definition['provider'])) {
+      $definition['provider_type'] = 'module';
+      $base_path = $this->moduleHandler->getModule($definition['provider'])->getPath();
+    }
+    elseif ($this->themeHandler->themeExists($definition['provider'])) {
+      $definition['provider_type'] = 'theme';
+      $base_path = $this->themeHandler->getTheme($definition['provider'])->getPath();
+    }
+    else {
+      $base_path = '';
+    }
+    $definition['path'] = !empty($definition['path']) ? $base_path . '/' . $definition['path'] : NULL;
+
+    // Either a theme or a template must be defined.
+    if (empty($definition['template']) && empty($definition['theme'])) {
+      throw new InvalidPluginDefinitionException($plugin_id);
+    }
+
+    if (empty($definition['template'])) {
+      $definition['template'] = strtr($definition['theme'], '_', '-');
+    }
+    elseif (empty($definition['theme'])) {
+      $definition['theme'] = strtr($definition['template'], '-', '_');
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getLayout($layout_id) {
+    $layout_definitions = $this->getDefinitions();
+    if (!$layout_id || !isset($layout_definitions[$layout_id])) {
+      return [];
+    }
+
+    return $layout_definitions[$layout_id];
+  }
+
+}
diff --git a/core/modules/field_layout/src/LayoutRepositoryInterface.php b/core/modules/field_layout/src/LayoutRepositoryInterface.php
new file mode 100644
index 0000000..0587d55
--- /dev/null
+++ b/core/modules/field_layout/src/LayoutRepositoryInterface.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace Drupal\field_layout;
+
+use Drupal\Component\Plugin\Discovery\DiscoveryInterface;
+
+/**
+ * Provides the interface for a repository of field layouts.
+ *
+ * @todo Replace with layout_plugin in https://www.drupal.org/node/2296423.
+ */
+interface LayoutRepositoryInterface extends DiscoveryInterface {
+
+  /**
+   * Gets sorted plugin definitions grouped by category.
+   *
+   * In addition to grouping, both categories and its entries are sorted,
+   * whereas plugin definitions are sorted by label.
+   *
+   * @see \Drupal\Component\Plugin\CategorizingPluginManagerInterface()
+   *
+   * @param array[]|null $definitions
+   *   (optional) The plugin definitions to group. If omitted, all plugin
+   *   definitions are used.
+   *
+   * @return array[]
+   *   Keys are category names, and values are arrays of which the keys are
+   *   plugin IDs and the values are plugin definitions.
+   */
+  public function getGroupedDefinitions(array $definitions = NULL);
+
+  /**
+   * Gets the layout definition for a given layout ID.
+   *
+   * @param string $layout_id
+   *   The layout ID.
+   *
+   * @return mixed[]
+   *   The layout definition for the given display.
+   */
+  public function getLayout($layout_id);
+
+}
diff --git a/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.info.yml b/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.info.yml
new file mode 100644
index 0000000..4d699e4
--- /dev/null
+++ b/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.info.yml
@@ -0,0 +1,8 @@
+name: 'Field Layout test'
+type: module
+description: 'Support module for Field Layout tests.'
+core: 8.x
+package: Testing
+version: VERSION
+dependencies:
+  - entity_test
diff --git a/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.routing.yml b/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.routing.yml
new file mode 100644
index 0000000..bcea288
--- /dev/null
+++ b/core/modules/field_layout/tests/modules/field_layout_test/field_layout_test.routing.yml
@@ -0,0 +1,7 @@
+entity.entity_test.test_view_mode:
+  path: '/entity_test/{entity_test}/test'
+  defaults:
+    _entity_view: 'entity_test.test'
+    _title: 'Test test view mode'
+  requirements:
+    _entity_access: 'entity_test.view'
diff --git a/core/modules/field_layout/tests/src/Functional/FieldLayoutTest.php b/core/modules/field_layout/tests/src/Functional/FieldLayoutTest.php
new file mode 100644
index 0000000..35b4bdd
--- /dev/null
+++ b/core/modules/field_layout/tests/src/Functional/FieldLayoutTest.php
@@ -0,0 +1,76 @@
+<?php
+
+namespace Drupal\Tests\field_layout\Functional;
+
+use Drupal\Tests\BrowserTestBase;
+
+/**
+ * Tests using field layout for entity displays.
+ *
+ * @group field_layout
+ */
+class FieldLayoutTest extends BrowserTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['field_layout', 'field_ui', 'node'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->createContentType([
+      'type' => 'article',
+    ]);
+    $this->createNode([
+      'type' => 'article',
+      'title' => 'The node title',
+      'body' => [[
+        'value' => 'The node body',
+      ]],
+    ]);
+    $this->drupalLogin($this->drupalCreateUser([
+      'access administration pages',
+      'administer content types',
+      'administer nodes',
+      'administer node fields',
+      'administer node display',
+      'administer node form display',
+      'view the administration theme',
+    ]));
+  }
+
+  /**
+   * Tests an entity type that has fields shown by default.
+   */
+  public function testNodeView() {
+    // By default, the one column layout is used.
+    $this->drupalGet('node/1');
+    $this->assertSession()->elementExists('css', '.field-layout--onecol');
+    $this->assertSession()->elementExists('css', '.field-layout-region--content .field--name-body');
+
+    $this->drupalGet('admin/structure/types/manage/article/display');
+    $this->assertEquals(['Content', 'Disabled'], $this->getRegionTitles());
+    $this->assertSession()->optionExists('fields[body][region]', 'content');
+  }
+
+  /**
+   * Gets the region titles on the page.
+   *
+   * @return string[]
+   *   An array of region titles.
+   */
+  protected function getRegionTitles() {
+    $region_titles = [];
+    $region_title_elements = $this->getSession()->getPage()->findAll('css', '.region-title td');
+    /** @var \Behat\Mink\Element\NodeElement[] $region_title_elements */
+    foreach ($region_title_elements as $region_title_element) {
+      $region_titles[] = $region_title_element->getText();
+    }
+    return $region_titles;
+  }
+
+}
diff --git a/core/modules/field_layout/tests/src/FunctionalJavascript/FieldLayoutTest.php b/core/modules/field_layout/tests/src/FunctionalJavascript/FieldLayoutTest.php
new file mode 100644
index 0000000..c3517ad
--- /dev/null
+++ b/core/modules/field_layout/tests/src/FunctionalJavascript/FieldLayoutTest.php
@@ -0,0 +1,224 @@
+<?php
+
+namespace Drupal\Tests\field_layout\FunctionalJavascript;
+
+use Drupal\entity_test\Entity\EntityTest;
+use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
+
+/**
+ * Tests using field layout for entity displays.
+ *
+ * @group field_layout
+ */
+class FieldLayoutTest extends JavascriptTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['field_layout', 'field_ui', 'field_layout_test'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $entity = EntityTest::create([
+      'name' => 'The name for this entity',
+      'field_test_text' => [[
+        'value' => 'The field test text value',
+      ]],
+    ]);
+    $entity->save();
+    $this->drupalLogin($this->drupalCreateUser([
+      'access administration pages',
+      'view test entity',
+      'administer entity_test content',
+      'administer entity_test fields',
+      'administer entity_test display',
+      'administer entity_test form display',
+      'view the administration theme',
+    ]));
+  }
+
+  /**
+   * Tests that layouts are unique per-view mode.
+   */
+  public function testEntityViewModes() {
+    // By default, the field is not visible.
+    $this->drupalGet('entity_test/1/test');
+    $this->assertSession()->elementNotExists('css', '.field-layout-region--content .field--name-field-test-text');
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->elementNotExists('css', '.field-layout-region--content .field--name-field-test-text');
+
+    // Change the layout for the "test" view mode. See
+    // core.entity_view_mode.entity_test.test.yml.
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    $this->click('#edit-modes');
+    $this->getSession()->getPage()->checkField('display_modes_custom[test]');
+    $this->submitForm([], 'Save');
+    $this->clickLink('configure them');
+    $this->getSession()->getPage()->pressButton('Show row weights');
+    $this->getSession()->getPage()->selectFieldOption('fields[field_test_text][region]', 'content');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->submitForm([], 'Save');
+
+    // Each view mode has a different layout.
+    $this->drupalGet('entity_test/1/test');
+    $this->assertSession()->elementExists('css', '.field-layout-region--content .field--name-field-test-text');
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->elementNotExists('css', '.field-layout-region--content .field--name-field-test-text');
+  }
+
+  /**
+   * Tests the use of field layout for entity form displays.
+   */
+  public function testEntityForm() {
+    // By default, the one column layout is used.
+    $this->drupalGet('entity_test/manage/1/edit');
+    $this->assertFieldInRegion('field_test_text[0][value]', 'content');
+
+    // The one column layout is in use.
+    $this->drupalGet('entity_test/structure/entity_test/form-display');
+    $this->assertEquals(['Content', 'Disabled'], $this->getRegionTitles());
+
+    // Switch the layout to two columns.
+    $this->click('#edit-field-layouts');
+    $this->getSession()->getPage()->selectFieldOption('field_layout', 'twocol');
+    $this->submitForm([], 'Save');
+
+    // The field is moved to the default region for the new layout.
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+    $this->assertEquals(['Left', 'Right', 'Disabled'], $this->getRegionTitles());
+
+    $this->drupalGet('entity_test/manage/1/edit');
+    // No fields are visible, and the regions don't display when empty.
+    $this->assertFieldInRegion('field_test_text[0][value]', 'left');
+    $this->assertSession()->elementExists('css', '.field-layout-region--left .field--name-field-test-text');
+
+    // After a refresh the new regions are still there.
+    $this->drupalGet('entity_test/structure/entity_test/form-display');
+    $this->assertEquals(['Left', 'Right', 'Disabled'], $this->getRegionTitles());
+
+    // Drag the field to the right region.
+    $field_test_text_row = $this->getSession()->getPage()->find('css', '#field-test-text');
+    $left_region_row = $this->getSession()->getPage()->find('css', '.region-right-message');
+    $field_test_text_row->find('css', '.handle')->dragTo($left_region_row);
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+
+    // The new layout is used.
+    $this->drupalGet('entity_test/manage/1/edit');
+    $this->assertSession()->elementExists('css', '.field-layout-region--right .field--name-field-test-text');
+    $this->assertFieldInRegion('field_test_text[0][value]', 'right');
+
+    // Move the field to the right region without tabledrag.
+    $this->drupalGet('entity_test/structure/entity_test/form-display');
+    $this->getSession()->getPage()->pressButton('Show row weights');
+    $this->getSession()->getPage()->selectFieldOption('fields[field_test_text][region]', 'right');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+
+    // The updated region is used.
+    $this->drupalGet('entity_test/manage/1/edit');
+    $this->assertFieldInRegion('field_test_text[0][value]', 'right');
+
+    // The layout is still in use without Field UI.
+    $this->container->get('module_installer')->uninstall(['field_ui']);
+    $this->drupalGet('entity_test/manage/1/edit');
+    $this->assertFieldInRegion('field_test_text[0][value]', 'right');
+  }
+
+  /**
+   * Tests the use of field layout for entity view displays.
+   */
+  public function testEntityView() {
+    // The one column layout is in use.
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    $this->assertEquals(['Content', 'Disabled'], $this->getRegionTitles());
+
+    // Switch the layout to two columns.
+    $this->click('#edit-field-layouts');
+    $this->getSession()->getPage()->selectFieldOption('field_layout', 'twocol');
+    $this->submitForm([], 'Save');
+
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+    $this->assertEquals(['Left', 'Right', 'Disabled'], $this->getRegionTitles());
+
+    $this->drupalGet('entity_test/1');
+    // No fields are visible, and the regions don't display when empty.
+    $this->assertSession()->elementNotExists('css', '.field-layout--twocol');
+    $this->assertSession()->elementNotExists('css', '.field-layout-region');
+    $this->assertSession()->elementNotExists('css', '.field--name-field-test-text');
+
+    // After a refresh the new regions are still there.
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    $this->assertEquals(['Left', 'Right', 'Disabled'], $this->getRegionTitles());
+
+    // Drag the field to the left region.
+    $this->assertTrue($this->assertSession()->optionExists('fields[field_test_text][type]', 'hidden')->isSelected());
+    $field_test_text_row = $this->getSession()->getPage()->find('css', '#field-test-text');
+    $left_region_row = $this->getSession()->getPage()->find('css', '.region-left-message');
+    $field_test_text_row->find('css', '.handle')->dragTo($left_region_row);
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertFalse($this->assertSession()->optionExists('fields[field_test_text][type]', 'hidden')->isSelected());
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+
+    // The new layout is used.
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->elementExists('css', '.field-layout--twocol');
+    $this->assertSession()->elementExists('css', '.field-layout-region--left .field--name-field-test-text');
+
+    // Move the field to the right region without tabledrag.
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    $this->getSession()->getPage()->pressButton('Show row weights');
+    $this->getSession()->getPage()->selectFieldOption('fields[field_test_text][region]', 'right');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->submitForm([], 'Save');
+    $this->assertSession()->pageTextContains('Your settings have been saved.');
+
+    // The updated region is used.
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->elementExists('css', '.field-layout-region--right .field--name-field-test-text');
+
+    // The layout is still in use without Field UI.
+    $this->container->get('module_installer')->uninstall(['field_ui']);
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->elementExists('css', '.field-layout--twocol');
+    $this->assertSession()->elementExists('css', '.field-layout-region--right .field--name-field-test-text');
+  }
+
+  /**
+   * Gets the region titles on the page.
+   *
+   * @return string[]
+   *   An array of region titles.
+   */
+  protected function getRegionTitles() {
+    $region_titles = [];
+    $region_title_elements = $this->getSession()->getPage()->findAll('css', '.region-title td');
+    /** @var \Behat\Mink\Element\NodeElement[] $region_title_elements */
+    foreach ($region_title_elements as $region_title_element) {
+      $region_titles[] = $region_title_element->getText();
+    }
+    return $region_titles;
+  }
+
+  /**
+   * Asserts that a field exists in a given region.
+   *
+   * @param string $field_selector
+   *   The field selector, one of field id|name|label|value.
+   * @param string $region_name
+   *   The machine name of the region.
+   */
+  protected function assertFieldInRegion($field_selector, $region_name) {
+    $region_element = $this->getSession()->getPage()->find('css', ".field-layout-region--$region_name");
+    $this->assertNotNull($region_element);
+    $this->assertSession()->fieldExists($field_selector, $region_element);
+  }
+
+}
diff --git a/core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php b/core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php
new file mode 100644
index 0000000..3a08663
--- /dev/null
+++ b/core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php
@@ -0,0 +1,247 @@
+<?php
+
+namespace Drupal\Tests\field_layout\Unit;
+
+use Drupal\Core\Entity\EntityFieldManagerInterface;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+use Drupal\field_layout\FieldLayoutBuilder;
+use Drupal\field_layout\LayoutRepositoryInterface;
+use Drupal\Tests\UnitTestCase;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\field_layout\FieldLayoutBuilder
+ * @group field_layout
+ */
+class FieldLayoutBuilderTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\field_layout\LayoutRepository|\Prophecy\Prophecy\ProphecyInterface
+   */
+  protected $layoutRepository;
+
+  /**
+   * @var \Drupal\Core\Entity\EntityFieldManagerInterface|\Prophecy\Prophecy\ProphecyInterface
+   */
+  protected $entityFieldManager;
+
+  /**
+   * @var \Drupal\field_layout\FieldLayoutBuilder
+   */
+  protected $fieldLayoutBuilder;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->layoutRepository = $this->prophesize(LayoutRepositoryInterface::class);
+    $this->layoutRepository->getLayout('unknown')->willReturn([]);
+    $this->layoutRepository->getLayout('twocol')->willReturn([
+      'library' => 'field_layout/drupal.field_layout.twocol',
+      'theme' => 'field_layout__twocol',
+      'regions' => [
+        'left' => [
+          'label' => 'Left',
+        ],
+        'right' => [
+          'label' => 'Right',
+        ],
+      ],
+    ]);
+    $this->entityFieldManager = $this->prophesize(EntityFieldManagerInterface::class);
+    $this->fieldLayoutBuilder = new FieldLayoutBuilder($this->layoutRepository->reveal(), $this->entityFieldManager->reveal());
+  }
+
+  /**
+   * @covers ::build
+   * @covers ::getFields
+   */
+  public function testBuildView() {
+    $definitions = [];
+    $non_configurable_field_definition = $this->prophesize(FieldDefinitionInterface::class);
+    $non_configurable_field_definition->isDisplayConfigurable('view')->willReturn(FALSE);
+    $definitions['non_configurable_field'] = $non_configurable_field_definition->reveal();
+    $this->entityFieldManager->getFieldDefinitions('the_entity_type_id', 'the_entity_type_bundle')->willReturn($definitions);
+
+    $build = [
+      'test1' => [
+        '#markup' => 'Test1',
+      ],
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+    ];
+
+    $display = $this->prophesize(EntityDisplayWithLayoutInterface::class);
+    $display->getTargetEntityTypeId()->willReturn('the_entity_type_id');
+    $display->getTargetBundle()->willReturn('the_entity_type_bundle');
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getComponents()->willReturn([
+      'test1' => [
+        'region' => 'right',
+      ],
+      'non_configurable_field' => [
+        'region' => 'left',
+      ],
+    ]);
+
+    $display_context = 'view';
+
+    $expected = [
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+      'field_layout' => [
+        '#theme' => 'field_layout__twocol',
+        '#attached' => [
+          'library' => [
+            'field_layout/drupal.field_layout.twocol',
+          ],
+        ],
+        'left' => [],
+        'right' => [
+          'test1' => [
+            '#markup' => 'Test1',
+          ],
+        ],
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertSame($expected, $build);
+  }
+
+  /**
+   * @covers ::build
+   * @covers ::getFields
+   */
+  public function testBuildForm() {
+    $definitions = [];
+    $non_configurable_field_definition = $this->prophesize(FieldDefinitionInterface::class);
+    $non_configurable_field_definition->isDisplayConfigurable('form')->willReturn(FALSE);
+    $definitions['non_configurable_field'] = $non_configurable_field_definition->reveal();
+    $this->entityFieldManager->getFieldDefinitions('the_entity_type_id', 'the_entity_type_bundle')->willReturn($definitions);
+
+    $build = [
+      'test1' => [
+        '#markup' => 'Test1',
+      ],
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+    ];
+
+    $display = $this->prophesize(EntityDisplayWithLayoutInterface::class);
+    $display->getTargetEntityTypeId()->willReturn('the_entity_type_id');
+    $display->getTargetBundle()->willReturn('the_entity_type_bundle');
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getComponents()->willReturn([
+      'test1' => [
+        'region' => 'right',
+      ],
+      'non_configurable_field' => [
+        'region' => 'left',
+      ],
+    ]);
+
+    $display_context = 'form';
+
+    $expected = [
+      'test1' => [
+        '#markup' => 'Test1',
+        '#group' => 'right',
+      ],
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+      'field_layout' => [
+        '#theme' => 'field_layout__twocol',
+        '#attached' => [
+          'library' => [
+            'field_layout/drupal.field_layout.twocol',
+          ],
+        ],
+        'left' => [
+          '#process' => ['\Drupal\Core\Render\Element\RenderElement::processGroup'],
+          '#pre_render' => ['\Drupal\Core\Render\Element\RenderElement::preRenderGroup'],
+        ],
+        'right' => [
+          '#process' => ['\Drupal\Core\Render\Element\RenderElement::processGroup'],
+          '#pre_render' => ['\Drupal\Core\Render\Element\RenderElement::preRenderGroup'],
+        ],
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertSame($expected, $build);
+  }
+
+  /**
+   * @covers ::build
+   */
+  public function testBuildEmpty() {
+    $definitions = [];
+    $non_configurable_field_definition = $this->prophesize(FieldDefinitionInterface::class);
+    $non_configurable_field_definition->isDisplayConfigurable('form')->willReturn(FALSE);
+    $definitions['non_configurable_field'] = $non_configurable_field_definition->reveal();
+    $this->entityFieldManager->getFieldDefinitions('the_entity_type_id', 'the_entity_type_bundle')->willReturn($definitions);
+
+    $build = [
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+    ];
+
+    $display = $this->prophesize(EntityDisplayWithLayoutInterface::class);
+    $display->getTargetEntityTypeId()->willReturn('the_entity_type_id');
+    $display->getTargetBundle()->willReturn('the_entity_type_bundle');
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getComponents()->willReturn([
+      'test1' => [
+        'region' => 'right',
+      ],
+      'non_configurable_field' => [
+        'region' => 'left',
+      ],
+    ]);
+
+    $display_context = 'form';
+
+    $expected = [
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertSame($expected, $build);
+  }
+
+  /**
+   * @covers ::build
+   */
+  public function testBuildNoLayout() {
+    $this->entityFieldManager->getFieldDefinitions(Argument::any(), Argument::any())->shouldNotBeCalled();
+
+    $build = [
+      'test1' => [
+        '#markup' => 'Test1',
+      ],
+    ];
+
+    $display = $this->prophesize(EntityDisplayWithLayoutInterface::class);
+    $display->getLayoutId()->willReturn('unknown');
+    $display->getComponents()->shouldNotBeCalled();
+
+    $display_context = 'form';
+
+    $expected = [
+      'test1' => [
+        '#markup' => 'Test1',
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertSame($expected, $build);
+  }
+
+}
diff --git a/core/modules/field_layout/tests/src/Unit/LayoutRepositoryTest.php b/core/modules/field_layout/tests/src/Unit/LayoutRepositoryTest.php
new file mode 100644
index 0000000..dc70ebc
--- /dev/null
+++ b/core/modules/field_layout/tests/src/Unit/LayoutRepositoryTest.php
@@ -0,0 +1,86 @@
+<?php
+
+namespace Drupal\Tests\field_layout\Unit;
+
+use Drupal\Core\Extension\Extension;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\Extension\ThemeHandlerInterface;
+use Drupal\field_layout\LayoutRepository;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\field_layout\LayoutRepository
+ * @group field_layout
+ */
+class LayoutRepositoryTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
+  /**
+   * @var \Drupal\field_layout\LayoutRepository
+   */
+  protected $layoutRepository;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->moduleHandler = $this->prophesize(ModuleHandlerInterface::class);
+    $this->moduleHandler->moduleExists('field_layout')->willReturn(TRUE);
+    $extension = new Extension('/', 'module', 'core/modules/field_layout/field_layout.info.yml');
+    $this->moduleHandler->getModule('field_layout')->willReturn($extension);
+
+    $this->themeHandler = $this->prophesize(ThemeHandlerInterface::class);
+
+    $this->layoutRepository = new LayoutRepository($this->moduleHandler->reveal(), $this->themeHandler->reveal(), $this->getStringTranslationStub());
+  }
+
+  /**
+   * @covers ::getDefinitions
+   */
+  public function testGetDefinitions() {
+    $expected = ['onecol', 'twocol'];
+
+    $layout_definitions = $this->layoutRepository->getDefinitions();
+    $this->assertEquals($expected, array_keys($layout_definitions));
+  }
+
+  /**
+   * @covers ::getLayout
+   */
+  public function testGetLayout() {
+    $expected = [
+      'label' => 'Two column',
+      'theme' => 'field_layout__twocol',
+      'provider' => 'field_layout',
+      'category' => 'Columns: 2',
+      'default_region' => 'left',
+      'regions' => [
+        'left' => [
+          'label' => 'Left',
+        ],
+        'right' => [
+          'label' => 'Right',
+        ],
+      ],
+      'path' => 'core/modules/field_layout/layouts/twocol',
+      'template' => 'field-layout--twocol',
+      'layout' => 'twocol',
+      'library' => 'field_layout/drupal.field_layout.twocol',
+      'provider_type' => 'module',
+    ];
+    $layout_definition = $this->layoutRepository->getLayout('twocol');
+    $this->assertEquals($expected, $layout_definition);
+  }
+
+}