diff --git a/core/composer.json b/core/composer.json
index 8b6f62f..c52add0 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..afe2da4
--- /dev/null
+++ b/core/modules/field_layout/config/schema/field_layout.schema.yml
@@ -0,0 +1,16 @@
+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:
+    id:
+      type: string
+      label: 'Layout ID'
+    settings:
+      type: layout_plugin.settings.[%parent.id]
+      label: 'Layout settings'
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..67f2ba0
--- /dev/null
+++ b/core/modules/field_layout/field_layout.info.yml
@@ -0,0 +1,8 @@
+name: 'Field Layout'
+type: module
+description: 'Adds layout capabilities to the Field UI.'
+package: Core (Experimental)
+version: VERSION
+core: 8.x
+dependencies:
+  - layout_plugin
diff --git a/core/modules/field_layout/field_layout.install b/core/modules/field_layout/field_layout.install
new file mode 100644
index 0000000..6f94674
--- /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 ::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.layouts.yml b/core/modules/field_layout/field_layout.layouts.yml
new file mode 100644
index 0000000..b8c6ef3
--- /dev/null
+++ b/core/modules/field_layout/field_layout.layouts.yml
@@ -0,0 +1,21 @@
+onecol:
+  label: 'One column'
+  path: layouts/onecol
+  template: field-layout--onecol
+  category: 'Columns: 1'
+  default_region: content
+  regions:
+    content:
+      label: Content
+twocol:
+  label: 'Two column'
+  path: layouts/twocol
+  template: field-layout--twocol
+  library: field_layout/drupal.field_layout.twocol
+  category: 'Columns: 2'
+  default_region: left
+  regions:
+    left:
+      label: Left
+    right:
+      label: Right
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..1a4806a
--- /dev/null
+++ b/core/modules/field_layout/field_layout.module
@@ -0,0 +1,69 @@
+<?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);
+    $entity_types['entity_form_display']->setFormClass('edit', FieldLayoutEntityFormDisplayEditForm::class);
+  }
+}
+
+/**
+ * Implements hook_entity_view_alter().
+ */
+function field_layout_entity_view_alter(array &$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');
+    }
+  }
+}
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..15204ac
--- /dev/null
+++ b/core/modules/field_layout/src/Display/EntityDisplayWithLayoutInterface.php
@@ -0,0 +1,56 @@
+<?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();
+
+  /**
+   * Gets the layout settings for this display.
+   *
+   * @return mixed[]
+   *   The layout settings.
+   */
+  public function getLayoutSettings();
+
+  /**
+   * Sets the layout ID for this display.
+   *
+   * @param string|null $layout_id
+   *   Either a valid layout ID, or NULL to remove the layout setting.
+   * @param array $layout_settings
+   *   (optional) An array of settings for this layout.
+   *
+   * @return $this
+   */
+  public function setLayout($layout_id, array $layout_settings = []);
+
+  /**
+   * Gets the layout plugin for this display.
+   *
+   * @return \Drupal\layout_plugin\Plugin\Layout\LayoutInterface
+   *   The layout plugin.
+   */
+  public function getLayoutPlugin();
+
+}
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..3a3a5fa
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityDisplayTrait.php
@@ -0,0 +1,66 @@
+<?php
+
+namespace Drupal\field_layout\Entity;
+
+use Drupal\Core\Entity\EntityStorageInterface;
+
+/**
+ * Provides shared code for entity displays.
+ */
+trait FieldLayoutEntityDisplayTrait {
+
+  /**
+   * Gets a layout definition.
+   *
+   * @param string $layout_id
+   *   The layout ID.
+   *
+   * @return \Drupal\layout_plugin\Plugin\Layout\LayoutDefinition
+   *   The layout definition.
+   */
+  protected function getLayoutDefinition($layout_id) {
+    return \Drupal::service('plugin.manager.layout_plugin')->getDefinition($layout_id);
+  }
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::getLayoutId().
+   */
+  public function getLayoutId() {
+    return $this->getThirdPartySetting('field_layout', 'id');
+  }
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::getLayoutSettings().
+   */
+  public function getLayoutSettings() {
+    return $this->getThirdPartySetting('field_layout', 'settings', []);
+  }
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::setLayout().
+   */
+  public function setLayout($layout_id, array $layout_settings = []) {
+    $this->setThirdPartySetting('field_layout', 'id', $layout_id);
+    $this->setThirdPartySetting('field_layout', 'settings', $layout_settings);
+    return $this;
+  }
+
+  /**
+   * Implements \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface::getLayoutPlugin().
+   */
+  public function getLayoutPlugin() {
+    return \Drupal::service('plugin.manager.layout_plugin')->createInstance($this->getLayoutId(), $this->getLayoutSettings());
+  }
+
+  /**
+   * Overrides \Drupal\Core\Entity\EntityDisplayBase::preSave().
+   */
+  public function preSave(EntityStorageInterface $storage) {
+    if (!$this->getLayoutId()) {
+      $this->setLayout('onecol');
+    }
+
+    parent::preSave($storage);
+  }
+
+}
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..2f3111e
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityFormDisplay.php
@@ -0,0 +1,25 @@
+<?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() {
+    return $this->getLayoutDefinition($this->getLayoutId() ?: 'onecol')->getDefaultRegion();
+  }
+
+}
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..b527059
--- /dev/null
+++ b/core/modules/field_layout/src/Entity/FieldLayoutEntityViewDisplay.php
@@ -0,0 +1,25 @@
+<?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() {
+    return $this->getLayoutDefinition($this->getLayoutId() ?: 'onecol')->getDefaultRegion();
+  }
+
+}
diff --git a/core/modules/field_layout/src/FieldLayoutBuilder.php b/core/modules/field_layout/src/FieldLayoutBuilder.php
new file mode 100644
index 0000000..47c6de2
--- /dev/null
+++ b/core/modules/field_layout/src/FieldLayoutBuilder.php
@@ -0,0 +1,123 @@
+<?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 Drupal\layout_plugin\LayoutPluginManagerInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Builds a field layout.
+ */
+class FieldLayoutBuilder implements ContainerInjectionInterface {
+
+  /**
+   * The layout plugin manager.
+   *
+   * @var \Drupal\layout_plugin\LayoutPluginManagerInterface
+   */
+  protected $layoutPluginManager;
+
+  /**
+   * The entity field manager.
+   *
+   * @var \Drupal\Core\Entity\EntityFieldManagerInterface
+   */
+  protected $entityFieldManager;
+
+  /**
+   * FieldLayoutBuilder constructor.
+   *
+   * @param \Drupal\layout_plugin\LayoutPluginManagerInterface $layout_plugin_manager
+   * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
+   */
+  public function __construct(LayoutPluginManagerInterface $layout_plugin_manager, EntityFieldManagerInterface $entity_field_manager) {
+    $this->layoutPluginManager = $layout_plugin_manager;
+    $this->entityFieldManager = $entity_field_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container) {
+    return new static(
+      $container->get('plugin.manager.layout_plugin'),
+      $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 = $this->layoutPluginManager->getDefinition($display->getLayoutId(), FALSE);
+    if ($layout_definition && $fields = $this->getFields($build, $display, $display_context)) {
+      // Add the regions to the $build in the correct order.
+      $fill = [];
+      if ($display_context === 'form') {
+        $fill['#process'][] = '\Drupal\Core\Render\Element\RenderElement::processGroup';
+        $fill['#pre_render'][] = '\Drupal\Core\Render\Element\RenderElement::preRenderGroup';
+      }
+      $regions = array_fill_keys($layout_definition->getRegionNames(), $fill);
+
+      foreach ($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 {
+          $regions[$field['region']][$name] = $build[$name];
+          unset($build[$name]);
+        }
+      }
+      $build['field_layout'] = $display->getLayoutPlugin()->build($regions);
+    }
+  }
+
+  /**
+   * 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..b7fd07e
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityDisplayFormTrait.php
@@ -0,0 +1,191 @@
+<?php
+
+namespace Drupal\field_layout\Form;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Form\SubformState;
+use Drupal\Core\Plugin\PluginFormInterface;
+use Drupal\field_layout\Display\EntityDisplayWithLayoutInterface;
+
+/**
+ * Provides shared code for entity display forms.
+ */
+trait FieldLayoutEntityDisplayFormTrait {
+
+  /**
+   * The field layout plugin manager.
+   *
+   * @var \Drupal\layout_plugin\LayoutPluginManagerInterface
+   */
+  protected $layoutPluginManager;
+
+  /**
+   * Overrides \Drupal\field_ui\Form\EntityDisplayFormBase::getRegions().
+   */
+  public function getRegions() {
+    $regions = [];
+
+    $layout_definition = $this->layoutPluginManager->getDefinition($this->getEntity()->getLayoutId() ?: 'onecol');
+    foreach ($layout_definition->getRegions() 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;
+  }
+
+  /**
+   * Overrides \Drupal\field_ui\Form\EntityDisplayFormBase::form().
+   */
+  public function form(array $form, FormStateInterface $form_state) {
+    $form = parent::form($form, $form_state);
+
+    $form['field_layouts'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Layout settings'),
+    ];
+
+    $layout_plugin = $this->getLayoutPlugin($this->getEntity(), $form_state);
+
+    $form['field_layouts']['field_layout'] = [
+      '#type' => 'select',
+      '#title' => $this->t('Select a layout'),
+      '#options' => $this->layoutPluginManager->getLayoutOptions(),
+      '#default_value' => $layout_plugin->getPluginId(),
+      '#ajax' => [
+        'callback' => '::settingsAjax',
+        'wrapper' => 'field-layout-settings-wrapper',
+        'trigger_as' => ['name' => 'field_layout_change'],
+      ],
+    ];
+    $form['field_layouts']['submit'] = [
+      '#type' => 'submit',
+      '#name' => 'field_layout_change',
+      '#value' => $this->t('Change layout'),
+      '#submit' => ['::settingsAjaxSubmit'],
+      '#attributes' => ['class' => ['js-hide']],
+      '#ajax' => [
+        'callback' => '::settingsAjax',
+        'wrapper' => 'field-layout-settings-wrapper',
+      ],
+    ];
+
+    $form['field_layouts']['settings_wrapper'] = [
+      '#type' => 'container',
+      '#id' => 'field-layout-settings-wrapper',
+      '#tree' => TRUE,
+    ];
+
+    if ($layout_plugin instanceof PluginFormInterface) {
+      $form['field_layouts']['settings_wrapper']['layout_settings'] = [];
+      $subform_state = SubformState::createForSubform($form['field_layouts']['settings_wrapper']['layout_settings'], $form, $form_state);
+      $form['field_layouts']['settings_wrapper']['layout_settings'] = $layout_plugin->buildConfigurationForm($form['field_layouts']['settings_wrapper']['layout_settings'], $subform_state);
+    }
+
+    return $form;
+  }
+
+  /**
+   * Gets the layout plugin for the currently selected field layout.
+   *
+   * @param \Drupal\field_layout\Display\EntityDisplayWithLayoutInterface $entity
+   *   The current form entity.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The current state of the form.
+   *
+   * @return \Drupal\layout_plugin\Plugin\Layout\LayoutInterface
+   *   The layout plugin.
+   */
+  protected function getLayoutPlugin(EntityDisplayWithLayoutInterface $entity, FormStateInterface $form_state) {
+    if (!$layout_plugin = $form_state->get('layout_plugin')) {
+      $stored_layout_id = $entity->getLayoutId();
+      // If a new field layout was selected, use that. Otherwise try to use the
+      // stored layout. Finally, fall back to the one column layout.
+      $layout_id = $form_state->getValue('field_layout') ?: ($stored_layout_id ?: 'onecol');
+      // If the current layout is the stored layout, use the stored layout
+      // settings. Otherwise leave the settings empty.
+      $layout_settings = $layout_id === $stored_layout_id ? $entity->getLayoutSettings() : [];
+
+      $layout_plugin = $this->layoutPluginManager->createInstance($layout_id, $layout_settings);
+      $form_state->set('layout_plugin', $layout_plugin);
+    }
+    return $layout_plugin;
+  }
+
+  /**
+   * Ajax callback for the field layout settings form.
+   */
+  public static function settingsAjax($form, FormStateInterface $form_state) {
+    return $form['field_layouts']['settings_wrapper'];
+  }
+
+  /**
+   * Submit handler for the non-JS case.
+   */
+  public static function settingsAjaxSubmit($form, FormStateInterface $form_state) {
+    $form_state->set('layout_plugin', NULL);
+    $form_state->setRebuild();
+  }
+
+  /**
+   * Overrides \Drupal\field_ui\Form\EntityDisplayFormBase::validateForm().
+   */
+  public function validateForm(array &$form, FormStateInterface $form_state) {
+    parent::validateForm($form, $form_state);
+
+    $layout_plugin = $this->getLayoutPlugin($this->getEntity(), $form_state);
+    if ($layout_plugin instanceof PluginFormInterface) {
+      $subform_state = SubformState::createForSubform($form['field_layouts']['settings_wrapper']['layout_settings'], $form, $form_state);
+      $layout_plugin->validateConfigurationForm($form['field_layouts']['settings_wrapper']['layout_settings'], $subform_state);
+    }
+  }
+
+  /**
+   * Overrides \Drupal\field_ui\Form\EntityDisplayFormBase::submitForm().
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+    parent::submitForm($form, $form_state);
+
+    $entity = $this->getEntity();
+    $old_layout = $entity->getLayoutId();
+    $new_layout = $form_state->getValue('field_layout');
+
+    $layout_plugin = $this->getLayoutPlugin($entity, $form_state);
+    if ($layout_plugin instanceof PluginFormInterface) {
+      $layout_plugin->submitConfigurationForm($form['field_layouts']['settings_wrapper']['layout_settings'], SubformState::createForSubform($form['field_layouts']['settings_wrapper']['layout_settings'], $form, $form_state));
+    }
+    $entity->setLayout($new_layout, $layout_plugin->getConfiguration());
+
+    // If the layout is changing, reset all fields.
+    if ($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..20719c3
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityFormDisplayEditForm.php
@@ -0,0 +1,46 @@
+<?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\layout_plugin\LayoutPluginManagerInterface;
+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\layout_plugin\LayoutPluginManagerInterface $field_layout_plugin_manager
+   *   The field layout plugin manager.
+   */
+  public function __construct(FieldTypePluginManagerInterface $field_type_manager, PluginManagerBase $plugin_manager, LayoutPluginManagerInterface $field_layout_plugin_manager) {
+    parent::__construct($field_type_manager, $plugin_manager);
+    $this->layoutPluginManager = $field_layout_plugin_manager;
+  }
+
+  /**
+   * {@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('plugin.manager.layout_plugin')
+    );
+  }
+
+}
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..f3da650
--- /dev/null
+++ b/core/modules/field_layout/src/Form/FieldLayoutEntityViewDisplayEditForm.php
@@ -0,0 +1,46 @@
+<?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\layout_plugin\LayoutPluginManagerInterface;
+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\layout_plugin\LayoutPluginManagerInterface $field_layout_plugin_manager
+   *   The field layout plugin manager.
+   */
+  public function __construct(FieldTypePluginManagerInterface $field_type_manager, PluginManagerBase $plugin_manager, LayoutPluginManagerInterface $field_layout_plugin_manager) {
+    parent::__construct($field_type_manager, $plugin_manager);
+    $this->layoutPluginManager = $field_layout_plugin_manager;
+  }
+
+  /**
+   * {@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('plugin.manager.layout_plugin')
+    );
+  }
+
+}
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..3e91740
--- /dev/null
+++ b/core/modules/field_layout/tests/src/FunctionalJavascript/FieldLayoutTest.php
@@ -0,0 +1,266 @@
+<?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', '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->assertSession()->assertWaitOnAjaxRequest();
+    $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');
+    $right_region_row = $this->getSession()->getPage()->find('css', '.region-right-message');
+    $field_test_text_row->find('css', '.handle')->dragTo($right_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->assertSession()->assertWaitOnAjaxRequest();
+    $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');
+  }
+
+  /**
+   * Tests layout plugins with forms.
+   */
+  public function testLayoutForms() {
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    // Switch to a field layout with settings.
+    $this->click('#edit-field-layouts');
+
+    // Test switching between layouts with and without forms.
+    $this->getSession()->getPage()->selectFieldOption('field_layout', 'layout_test_plugin');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertSession()->fieldExists('settings_wrapper[layout_settings][setting_1]');
+
+    $this->getSession()->getPage()->selectFieldOption('field_layout', 'layout_test_2col');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertSession()->fieldNotExists('settings_wrapper[layout_settings][setting_1]');
+
+    $this->getSession()->getPage()->selectFieldOption('field_layout', 'layout_test_plugin');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->assertSession()->fieldExists('settings_wrapper[layout_settings][setting_1]');
+
+    // Move the test field to the content region.
+    $this->getSession()->getPage()->pressButton('Show row weights');
+    $this->getSession()->getPage()->selectFieldOption('fields[field_test_text][region]', 'content');
+    $this->assertSession()->assertWaitOnAjaxRequest();
+    $this->submitForm([], 'Save');
+
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->pageTextContains('Blah: Default');
+
+    // Update the field layout settings.
+    $this->drupalGet('entity_test/structure/entity_test/display');
+    $this->click('#edit-field-layouts');
+    $this->getSession()->getPage()->fillField('settings_wrapper[layout_settings][setting_1]', 'Test text');
+    $this->submitForm([], 'Save');
+
+    $this->drupalGet('entity_test/1');
+    $this->assertSession()->pageTextContains('Blah: 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..9fa4ada
--- /dev/null
+++ b/core/modules/field_layout/tests/src/Unit/FieldLayoutBuilderTest.php
@@ -0,0 +1,281 @@
+<?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\layout_plugin\LayoutPluginManagerInterface;
+use Drupal\layout_plugin\Plugin\Layout\LayoutDefault;
+use Drupal\layout_plugin\Plugin\Layout\LayoutDefinition;
+use Drupal\Tests\UnitTestCase;
+use Prophecy\Argument;
+
+/**
+ * @coversDefaultClass \Drupal\field_layout\FieldLayoutBuilder
+ * @group field_layout
+ */
+class FieldLayoutBuilderTest extends UnitTestCase {
+
+  /**
+   * @var \Drupal\layout_plugin\LayoutPluginManager|\Prophecy\Prophecy\ProphecyInterface
+   */
+  protected $layoutPluginManager;
+
+  /**
+   * @var \Drupal\Core\Entity\EntityFieldManagerInterface|\Prophecy\Prophecy\ProphecyInterface
+   */
+  protected $entityFieldManager;
+
+  /**
+   * @var \Drupal\field_layout\FieldLayoutBuilder
+   */
+  protected $fieldLayoutBuilder;
+
+  /**
+   * @var \Drupal\layout_plugin\Plugin\Layout\LayoutInterface
+   */
+  protected $layoutPlugin;
+
+  /**
+   * @var \Drupal\layout_plugin\Plugin\Layout\LayoutDefinition
+   */
+  protected $pluginDefinition;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    $this->pluginDefinition = new LayoutDefinition([
+      'library' => 'field_layout/drupal.field_layout.twocol',
+      'theme_hook' => 'field_layout__twocol',
+      'regions' => [
+        'left' => [
+          'label' => 'Left',
+        ],
+        'right' => [
+          'label' => 'Right',
+        ],
+      ],
+    ]);
+    $this->layoutPlugin = new LayoutDefault([], 'twocol', $this->pluginDefinition);
+
+    $this->layoutPluginManager = $this->prophesize(LayoutPluginManagerInterface::class);
+    $this->layoutPluginManager->getDefinition('unknown', FALSE)->willReturn(NULL);
+    $this->layoutPluginManager->getDefinition('twocol', FALSE)->willReturn($this->pluginDefinition);
+
+    $this->entityFieldManager = $this->prophesize(EntityFieldManagerInterface::class);
+
+    $this->fieldLayoutBuilder = new FieldLayoutBuilder($this->layoutPluginManager->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');
+    $display->getLayoutPlugin()->willReturn($this->layoutPlugin);
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getLayoutSettings()->willReturn([]);
+    $display->getComponents()->willReturn([
+      'test1' => [
+        'region' => 'right',
+      ],
+      'non_configurable_field' => [
+        'region' => 'left',
+      ],
+    ]);
+
+    $display_context = 'view';
+
+    $expected = [
+      'non_configurable_field' => [
+        '#markup' => 'Non-configurable',
+      ],
+      'field_layout' => [
+        '#content' => [
+          'left' => [],
+          'right' => [
+            'test1' => [
+              '#markup' => 'Test1',
+            ],
+          ],
+        ],
+        '#settings' => [],
+        '#layout' => $this->pluginDefinition,
+        '#theme' => 'field_layout__twocol',
+        '#attached' => [
+          'library' => [
+            'field_layout/drupal.field_layout.twocol',
+          ],
+        ],
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertEquals($expected, $build);
+    $this->assertSame($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');
+    $display->getLayoutPlugin()->willReturn($this->layoutPlugin);
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getLayoutSettings()->willReturn([]);
+    $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' => [
+        '#content' => [
+          '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'],
+          ],
+        ],
+        '#settings' => [],
+        '#layout' => $this->pluginDefinition,
+        '#theme' => 'field_layout__twocol',
+        '#attached' => [
+          'library' => [
+            'field_layout/drupal.field_layout.twocol',
+          ],
+        ],
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertEquals($expected, $build);
+    $this->assertSame($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');
+    $display->getLayoutPlugin()->willReturn($this->layoutPlugin);
+    $display->getLayoutId()->willReturn('twocol');
+    $display->getLayoutSettings()->willReturn([]);
+    $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->getLayoutSettings()->willReturn([]);
+    $display->getComponents()->shouldNotBeCalled();
+
+    $display_context = 'form';
+
+    $expected = [
+      'test1' => [
+        '#markup' => 'Test1',
+      ],
+    ];
+    $this->fieldLayoutBuilder->build($build, $display->reveal(), $display_context);
+    $this->assertSame($expected, $build);
+  }
+
+}