diff --git a/core/modules/settings_tray/settings_tray.module b/core/modules/settings_tray/settings_tray.module
index 48b08caaab..834c6f4515 100644
--- a/core/modules/settings_tray/settings_tray.module
+++ b/core/modules/settings_tray/settings_tray.module
@@ -9,8 +9,12 @@
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Url;
 use Drupal\settings_tray\Block\BlockEntityOffCanvasForm;
+use \Drupal\settings_tray\Form\BlockFormWithRelatedConfigInterface;
 use Drupal\settings_tray\Form\SystemBrandingOffCanvasForm;
 use Drupal\settings_tray\Form\SystemMenuOffCanvasForm;
+use Drupal\block\BlockInterface;
+use Drupal\block\Entity\Block;
+use \Drupal\Core\Plugin\PluginWithFormsInterface;
 
 /**
  * Implements hook_help().
@@ -54,6 +58,32 @@ function settings_tray_contextual_links_view_alter(&$element, $items) {
   }
 }
 
+/**
+ * Checks if a block has overrides.
+ *
+ * @param \Drupal\block\BlockInterface $block
+ *   The block to check for overrides.
+ *
+ * @return bool
+ *   TRUE if the block has overrides otherwise FALSE.
+ *
+ * @internal
+ */
+function _settings_tray_has_block_overrides(BlockInterface $block) {
+  $has_overrides = \Drupal::config($block->getEntityType()->getConfigPrefix() . '.' . $block->id())->hasOverrides();
+  if (!$has_overrides) {
+    // Check if the related config has overriddes
+    $block_plugin = $block->getPlugin();
+    if ($block_plugin instanceof PluginWithFormsInterface) {
+      $settings_tray_form = Drupal::service('plugin_form.factory')->createInstance($block_plugin, 'settings_tray', 'configure');
+      if($settings_tray_form instanceof BlockFormWithRelatedConfigInterface) {
+        $has_overrides = $settings_tray_form->hasOverriddenConfig();
+      }
+    }
+  }
+  return $has_overrides;
+}
+
 /**
  * Implements hook_block_view_alter().
  */
@@ -93,10 +123,14 @@ function settings_tray_preprocess_block(&$variables) {
   $block_plugin_manager = \Drupal::service('plugin.manager.block');
   /** @var \Drupal\Core\Block\BlockPluginInterface $block_plugin */
   $block_plugin = $block_plugin_manager->createInstance($variables['plugin_id']);
-  if ($access_checker->accessBlockPlugin($block_plugin)->isAllowed()) {
-    // Add class and attributes to all blocks to allow Javascript to target.
-    $variables['attributes']['class'][] = 'settings-tray-editable';
-    $variables['attributes']['data-drupal-settingstray'] = 'editable';
+  if (!empty($variables['elements']['#contextual_links']['block']['route_parameters']['block'])) {
+    $block_id = $variables['elements']['#contextual_links']['block']['route_parameters']['block'];
+    $block = Block::load($block_id);
+    if ($access_checker->accessBlockPlugin($block_plugin)->isAllowed() && !_settings_tray_has_block_overrides($block)) {
+      // Add class and attributes to all blocks to allow Javascript to target.
+      $variables['attributes']['class'][] = 'settings-tray-editable';
+      $variables['attributes']['data-drupal-settingstray'] = 'editable';
+    }
   }
 }
 
@@ -196,3 +230,15 @@ function settings_tray_css_alter(&$css, AttachedAssetsInterface $assets) {
     $css[$path]['group'] = 200;
   }
 }
+
+/**
+ * Implements hook_contextual_links_alter().
+ */
+function settings_tray_contextual_links_alter(array &$links, $group, array $route_parameters) {
+  if (isset($links['settings_tray.block_configure']['route_parameters']['block'])) {
+    $block = Block::load($links['settings_tray.block_configure']['route_parameters']['block']);
+    if (_settings_tray_has_block_overrides($block)) {
+      unset($links['settings_tray.block_configure']);
+    }
+  }
+}
diff --git a/core/modules/settings_tray/src/Form/BlockFormWithRelatedConfigInterface.php b/core/modules/settings_tray/src/Form/BlockFormWithRelatedConfigInterface.php
new file mode 100644
index 0000000000..9ae4dc6720
--- /dev/null
+++ b/core/modules/settings_tray/src/Form/BlockFormWithRelatedConfigInterface.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Drupal\settings_tray\Form;
+
+/**
+ * Any interface for forms with related configuration.
+ */
+interface BlockFormWithRelatedConfigInterface {
+
+  /**
+   * Determines if the related configuration is overridden.
+   *
+   * @return bool
+   *   TRUE if the related config for the form is in an overridden state
+   *   otherwise returns false.
+   */
+  public function hasOverriddenConfig();
+
+}
diff --git a/core/modules/settings_tray/src/Form/SystemBrandingOffCanvasForm.php b/core/modules/settings_tray/src/Form/SystemBrandingOffCanvasForm.php
index 0b4290e2fa..c7d8bf5aef 100644
--- a/core/modules/settings_tray/src/Form/SystemBrandingOffCanvasForm.php
+++ b/core/modules/settings_tray/src/Form/SystemBrandingOffCanvasForm.php
@@ -15,7 +15,7 @@
  *
  * @internal
  */
-class SystemBrandingOffCanvasForm extends PluginFormBase implements ContainerInjectionInterface {
+class SystemBrandingOffCanvasForm extends PluginFormBase implements ContainerInjectionInterface, BlockFormWithRelatedConfigInterface {
 
   /**
    * The block plugin.
@@ -103,4 +103,11 @@ public function submitConfigurationForm(array &$form, FormStateInterface $form_s
     $this->plugin->submitConfigurationForm($form, $form_state);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function hasOverriddenConfig() {
+    $config = $this->configFactory->get('system.site');
+    return $config->hasOverrides('name') || $config->hasOverrides('slogan');
+  }
 }
diff --git a/core/modules/settings_tray/src/Form/SystemMenuOffCanvasForm.php b/core/modules/settings_tray/src/Form/SystemMenuOffCanvasForm.php
index 15d19a87f9..3d202b6651 100644
--- a/core/modules/settings_tray/src/Form/SystemMenuOffCanvasForm.php
+++ b/core/modules/settings_tray/src/Form/SystemMenuOffCanvasForm.php
@@ -22,7 +22,7 @@
  *
  * @internal
  */
-class SystemMenuOffCanvasForm extends PluginFormBase implements ContainerInjectionInterface {
+class SystemMenuOffCanvasForm extends PluginFormBase implements ContainerInjectionInterface, BlockFormWithRelatedConfigInterface {
 
   use StringTranslationTrait;
   use RedirectDestinationTrait;
@@ -150,4 +150,11 @@ public function setPlugin(PluginInspectionInterface $plugin) {
     $this->menu = $this->menuStorage->load($this->plugin->getDerivativeId());
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function hasOverriddenConfig() {
+    return \Drupal::config($this->menu->getEntityType()->getConfigPrefix() . '.' . $this->menu->id())->hasOverrides();
+  }
+
 }
diff --git a/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.info.yml b/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.info.yml
new file mode 100644
index 0000000000..89f9732feb
--- /dev/null
+++ b/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.info.yml
@@ -0,0 +1,7 @@
+name: 'Configuration override test for Settings Tray'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+dependencies:
+  - settings_tray
diff --git a/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.services.yml b/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.services.yml
new file mode 100644
index 0000000000..b23035bde2
--- /dev/null
+++ b/core/modules/settings_tray/tests/modules/settings_tray_override_test/settings_tray_override_test.services.yml
@@ -0,0 +1,5 @@
+services:
+  settings_tray_override_test.overrider:
+    class: Drupal\settings_tray_override_test\ConfigOverrider
+    tags:
+      - { name: config.factory.override}
diff --git a/core/modules/settings_tray/tests/modules/settings_tray_override_test/src/ConfigOverrider.php b/core/modules/settings_tray/tests/modules/settings_tray_override_test/src/ConfigOverrider.php
new file mode 100644
index 0000000000..1171a1bb90
--- /dev/null
+++ b/core/modules/settings_tray/tests/modules/settings_tray_override_test/src/ConfigOverrider.php
@@ -0,0 +1,53 @@
+<?php
+
+namespace Drupal\settings_tray_override_test;
+
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Config\ConfigFactoryOverrideInterface;
+use Drupal\Core\Config\StorageInterface;
+
+/**
+ * Provides an overridden block for Settings Tray testing.
+ *
+ * @see \Drupal\Tests\settings_tray\FunctionalJavascript\SettingsTrayBlockFormTest::testOverriddenDisabled()
+ */
+class ConfigOverrider implements ConfigFactoryOverrideInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function loadOverrides($names) {
+    $overrides = [];
+    if (in_array('block.block.overridden_block', $names)) {
+      $overrides = $overrides + ['block.block.overridden_block' => ['settings' => ['label' => 'Now this will be the label.']]];
+    }
+    if (in_array('system.site', $names)) {
+      if ($site_name = \Drupal::state()->get('settings_tray_override_test.site_name')) {
+        $overrides = $overrides + ['system.site' => ['name' => $site_name]];
+      }
+    }
+    return $overrides;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheSuffix() {
+    return 'ConfigOverrider';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function createConfigObject($name, $collection = StorageInterface::DEFAULT_COLLECTION) {
+    return NULL;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheableMetadata($name) {
+    return new CacheableMetadata();
+  }
+
+}
diff --git a/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php b/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
index fcfecde400..c308d0edc3 100644
--- a/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
+++ b/core/modules/settings_tray/tests/src/FunctionalJavascript/SettingsTrayBlockFormTest.php
@@ -43,6 +43,7 @@ class SettingsTrayBlockFormTest extends OffCanvasTestBase {
     // cause test failures.
     'settings_tray_test_css',
     'settings_tray_test',
+    'settings_tray_override_test',
   ];
 
   /**
@@ -75,7 +76,7 @@ public function testBlocks($theme, $block_plugin, $new_page_text, $element_selec
     $page = $this->getSession()->getPage();
     $this->enableTheme($theme);
     $block = $this->placeBlock($block_plugin);
-    $block_selector = str_replace('_', '-', $this->getBlockSelector($block));
+    $block_selector = $this->getBlockSelector($block);
     $block_id = $block->id();
     $this->drupalGet('user');
 
@@ -267,8 +268,10 @@ protected function assertOffCanvasBlockFormIsValid() {
    * @param string $contextual_link_container
    *   The element that contains the contextual links. If none provide the
    *   $block_selector will be used.
+   * @param bool $has_confirm_form
+   *   Determines if the block form should be confirmed.
    */
-  protected function openBlockForm($block_selector, $contextual_link_container = '') {
+  protected function openBlockForm($block_selector, $contextual_link_container = '', $has_confirm_form = TRUE) {
     if (!$contextual_link_container) {
       $contextual_link_container = $block_selector;
     }
@@ -283,7 +286,9 @@ protected function openBlockForm($block_selector, $contextual_link_container = '
     $this->assertSession()->assertWaitOnAjaxRequest();
     $this->click($block_selector);
     $this->waitForOffCanvasToOpen();
-    $this->assertOffCanvasBlockFormIsValid();
+    if ($has_confirm_form) {
+      $this->assertOffCanvasBlockFormIsValid();
+    }
   }
 
   /**
@@ -321,7 +326,7 @@ public function testQuickEditLinks() {
       $this->enableTheme($theme);
 
       $block = $this->placeBlock($block_plugin);
-      $block_selector = str_replace('_', '-', $this->getBlockSelector($block));
+      $block_selector = $this->getBlockSelector($block);
       // Load the same page twice.
       foreach ([1, 2] as $page_load_times) {
         $this->drupalGet('node/' . $node->id());
@@ -531,7 +536,7 @@ public function testCustomBlockLinks() {
    *   The CSS selector.
    */
   public function getBlockSelector(Block $block) {
-    return '#block-' . $block->id();
+    return '#block-' . str_replace('_', '-', $block->id());
   }
 
   /**
@@ -577,4 +582,67 @@ protected function getTestThemes() {
     });
   }
 
+  /**
+   * Tests that blocks with configuration overrides are disabled.
+   */
+  public function testOverriddenDisabled() {
+    $web_assert = $this->assertSession();
+    $page = $this->getSession()->getPage();
+    $overridden_block = $this->placeBlock('system_powered_by_block', [
+      'id' => 'overridden_block',
+      'label_display' => 1,
+      'label' => 'This will be overridden.',
+    ]);
+    $this->drupalGet('user');
+    $this->assertOverriddenBlockDisabled($overridden_block, 'Now this will be the label.');
+
+    // Test a non-overridden block does show the form in the off-canvas dialog.
+    $block = $this->placeBlock('system_powered_by_block', [
+      'label_display' => 1,
+      'label' => 'Labely label',
+    ]);
+    $this->drupalGet('user');
+    $block_selector = $this->getBlockSelector($block);
+    // Confirm the block is marked as Settings Tray editable.
+    $this->assertEquals('editable', $page->find('css', $block_selector)->getAttribute('data-drupal-settingstray'));
+    // Confirm the label is not overridden.
+    $web_assert->elementContains('css', $block_selector, 'Labely label');
+    $this->enableEditMode();
+    $this->openBlockForm($this->getBlockSelector($block));
+
+    // Confirm the branding block is disabled when site name is overridden.
+    $overridden_name = 'The namey name';
+    $this->container->get('state')->set('settings_tray_override_test.site_name', $overridden_name);
+    $overridden_branding_block = $this->placeBlock('system_branding_block');
+    $this->drupalGet('user');
+    $this->assertOverriddenBlockDisabled($overridden_branding_block, $overridden_name);
+  }
+
+  /**
+   * Asserts that an overridden block has Settings Tray disabled.
+   *
+   * @param \Drupal\block\Entity\Block $overridden_block
+   *   The overridden block.
+   * @param string $override_text
+   *   The override text that should appear in the block.
+   */
+  protected function assertOverriddenBlockDisabled(Block $overridden_block, $override_text) {
+    $web_assert = $this->assertSession();
+    $page = $this->getSession()->getPage();
+    $block_selector = $this->getBlockSelector($overridden_block);
+    $block_id = $overridden_block->id();
+    // Confirm the block does not have a quick edit link.
+    $contextual_links = $page->findAll('css', "$block_selector .contextual-links li a");
+    $this->assertNotEmpty($contextual_links);
+    foreach ($contextual_links as $link) {
+      $this->assertNotContains("/admin/structure/block/manage/$block_id/off-canvas", $link->getAttribute('href'));
+    }
+    // Confirm the block is not marked as Settings Tray editable.
+    $this->assertFalse($page->find('css', $block_selector)
+      ->hasAttribute('data-drupal-settingstray'));
+
+    // Confirm the text is actually overridden.
+    $web_assert->elementContains('css', $this->getBlockSelector($overridden_block), $override_text);
+  }
+
 }
diff --git a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
index d3f446cf6a..86cca2c680 100644
--- a/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
+++ b/core/modules/system/tests/src/FunctionalJavascript/OffCanvasTestBase.php
@@ -9,6 +9,11 @@
  */
 abstract class OffCanvasTestBase extends JavascriptTestBase {
 
+  /**
+   * CSS selector for the off-canvas dialog.
+   */
+  const OFF_CANVAS_CSS_SELECTOR = '.ui-dialog[aria-describedby="drupal-off-canvas"]';
+
   /**
    * {@inheritdoc}
    */
@@ -83,7 +88,7 @@ protected function waitForOffCanvasToClose() {
    * @return \Behat\Mink\Element\NodeElement|null
    */
   protected function getOffCanvasDialog() {
-    $off_canvas_dialog = $this->getSession()->getPage()->find('css', '.ui-dialog[aria-describedby="drupal-off-canvas"]');
+    $off_canvas_dialog = $this->getSession()->getPage()->find('css', self::OFF_CANVAS_CSS_SELECTOR);
     $this->assertEquals(FALSE, empty($off_canvas_dialog), 'The off-canvas dialog was found.');
     return $off_canvas_dialog;
   }