diff --git a/core/modules/shortcut/tests/src/Functional/ShortcutCacheTagsTest.php b/core/modules/shortcut/tests/src/Functional/ShortcutCacheTagsTest.php
index e479610aef..3d8ad12801 100644
--- a/core/modules/shortcut/tests/src/Functional/ShortcutCacheTagsTest.php
+++ b/core/modules/shortcut/tests/src/Functional/ShortcutCacheTagsTest.php
@@ -159,13 +159,13 @@ public function testToolbar() {
     $this->drupalLogin($site_configuration_user1);
     $this->verifyDynamicPageCache($test_page_url, 'MISS');
     $this->verifyDynamicPageCache($test_page_url, 'HIT');
-    $this->assertCacheContexts(['user', 'url.query_args:_wrapper_format']);
+    $this->assertCacheContexts(['user', 'url.query_args:_wrapper_format', 'route']);
     $this->assertSession()->linkExists('Shortcuts');
     $this->assertSession()->linkExists('Cron');
 
     $this->drupalLogin($site_configuration_user2);
     $this->verifyDynamicPageCache($test_page_url, 'HIT');
-    $this->assertCacheContexts(['user', 'url.query_args:_wrapper_format']);
+    $this->assertCacheContexts(['user', 'url.query_args:_wrapper_format', 'route']);
     $this->assertSession()->linkExists('Shortcuts');
     $this->assertSession()->linkExists('Cron');
 
diff --git a/core/modules/toolbar/src/Controller/ToolbarController.php b/core/modules/toolbar/src/Controller/ToolbarController.php
index c94e35b307..6405955424 100644
--- a/core/modules/toolbar/src/Controller/ToolbarController.php
+++ b/core/modules/toolbar/src/Controller/ToolbarController.php
@@ -90,7 +90,11 @@ public static function preRenderAdministrationTray(array $element) {
    * @internal
    */
   public static function preRenderGetRenderedSubtrees(array $data) {
+    $output = '';
+    /** @var \Drupal\Core\Menu\MenuLinkTreeInterface $menu_tree */
     $menu_tree = \Drupal::service('toolbar.menu_tree');
+    /** @var \Drupal\Core\Menu\LocalTaskManagerInterface $local_task_manager */
+    $local_task_manager = \Drupal::service('plugin.manager.menu.local_task');
     // Load the administration menu. The first level is the "Administration"
     // link. In order to load the children of that link and the subsequent two
     // levels, start at the second level and end at the fourth.
@@ -108,13 +112,97 @@ public static function preRenderGetRenderedSubtrees(array $data) {
     // Calculated the combined cacheability of all subtrees.
     $cacheability = new CacheableMetadata();
     foreach ($tree as $element) {
+      // Get local tasks for this menu item and build render array.
+      $local_tasks = $local_task_manager->getTasksBuild($element->link->getRouteName(), $cacheability);
       /** @var \Drupal\Core\Menu\MenuLinkInterface $link */
       $link = $element->link;
       if ($element->subtree) {
         $subtree = $menu_tree->build($element->subtree);
+        if (count($local_tasks)) {
+          // Reduce the local tasks tree by elements already in the admin menu
+          // tree.
+          $local_tasks_subtree_reduced = [];
+          foreach ($local_tasks as $key => $tasks) {
+            foreach ($local_tasks[$key] as $task_key => $task) {
+              if (!isset($subtree['#items'][$task_key]) && $task_key != $element->link->getRouteName()) {
+                $local_tasks_subtree_reduced[$key][$task_key] = $task;
+              }
+            }
+          }
+          // Merge the local tasks into the existing 2nd level subtree.
+          if (count($local_tasks_subtree_reduced)) {
+            $local_tasks_subtree_build = _build_tasks_as_menu_tree($local_tasks_subtree_reduced);
+            $subtree['#items'] += $local_tasks_subtree_build['#items'];
+          }
+        }
+        foreach ($element->subtree as $sub_element) {
+          // Get local tasks for this sub menu item and build render array.
+          $sub_local_tasks = $local_task_manager->getTasksBuild($sub_element->link->getRouteName(), $cacheability);
+          $route_name = $sub_element->link->getRouteName();
+          $route_name_parent = $element->link->getRouteName();
+          if (count($sub_local_tasks)) {
+            $sub_local_tasks_subtree_reduced = [];
+            if (count($sub_element->subtree)) {
+              // Reduce the local tasks tree by elements already in the admin
+              // menu tree.
+              foreach ($sub_local_tasks as $key => $tasks) {
+                foreach ($sub_local_tasks[$key] as $task_key => $task) {
+                  if (!isset($subtree['#items'][$task_key])
+                  && !isset($subtree['#items'][$route_name]['below'][$task_key])
+                  && $task_key != $route_name
+                  && $task_key != $route_name_parent) {
+                    $sub_local_tasks_subtree_reduced[$key][$task_key] = $task;
+                  }
+                }
+              }
+              // Merge the local tasks into the existing 3rd level subtree.
+              if (count(current($sub_local_tasks_subtree_reduced))) {
+                $sub_local_tasks_subtree_build = _build_tasks_as_menu_tree($sub_local_tasks_subtree_reduced);
+                $subtree['#items'][$route_name]['below'] += $sub_local_tasks_subtree_build['#items'];
+              }
+            }
+            else {
+              // Reduce the local tasks tree by elements already in the admin
+              // menu tree.
+              foreach ($sub_local_tasks as $key => $tasks) {
+                foreach ($sub_local_tasks[$key] as $task_key => $task) {
+                  if (!isset($subtree['#items'][$task_key]) && $task_key != $route_name && $task_key != $route_name_parent) {
+                    $sub_local_tasks_subtree_reduced[$key][$task_key] = $task;
+                  }
+                }
+              }
+              // Add the local tasks as new 3rd level subtree.
+              if (!empty(current($sub_local_tasks_subtree_reduced))) {
+                $sub_local_tasks_subtree_build = _build_tasks_as_menu_tree($sub_local_tasks_subtree_reduced);
+                $subtree['#items'][$route_name]['below'] = $sub_local_tasks_subtree_build['#items'];
+              }
+            }
+          }
+        }
         $output = \Drupal::service('renderer')->renderPlain($subtree);
         $cacheability = $cacheability->merge(CacheableMetadata::createFromRenderArray($subtree));
       }
+      elseif (count($local_tasks)) {
+        // Reduce the local tasks tree by elements already in the admin menu
+        // tree.
+        $local_tasks_subtree_reduced = [];
+        foreach ($local_tasks as $key => $tasks) {
+          foreach ($local_tasks[$key] as $task_key => $task) {
+            if ($task_key != $element->link->getRouteName()) {
+              $local_tasks_subtree_reduced[$key][$task_key] = $task;
+            }
+          }
+        }
+        // Add the local tasks as new 2nd level subtree.
+        if (count($local_tasks_subtree_reduced)) {
+          $local_tasks_subtree_build = _build_tasks_as_menu_tree($local_tasks_subtree_reduced);
+          $output = \Drupal::service('renderer')->renderPlain($local_tasks_subtree_build);
+          $cacheability = $cacheability->merge(CacheableMetadata::createFromRenderArray($local_tasks_subtree_build));
+        }
+        else {
+          $output = '';
+        }
+      }
       else {
         $output = '';
       }
diff --git a/core/modules/toolbar/tests/src/Functional/ToolbarCacheContextsTest.php b/core/modules/toolbar/tests/src/Functional/ToolbarCacheContextsTest.php
index 6f49871828..76441f6579 100644
--- a/core/modules/toolbar/tests/src/Functional/ToolbarCacheContextsTest.php
+++ b/core/modules/toolbar/tests/src/Functional/ToolbarCacheContextsTest.php
@@ -80,23 +80,23 @@ public function testCacheIntegration() {
    */
   public function testToolbarCacheContextsCaller() {
     // Test with default combination and permission to see toolbar.
-    $this->assertToolbarCacheContexts(['user'], 'Expected cache contexts found for default combination and permission to see toolbar.');
+    $this->assertToolbarCacheContexts(['user', 'route'], 'Expected cache contexts found for default combination and permission to see toolbar.');
 
     // Test without user toolbar tab. User module is a required module so we have to
     // manually remove the user toolbar tab.
     $this->installExtraModules(['toolbar_disable_user_toolbar']);
-    $this->assertToolbarCacheContexts(['user.permissions'], 'Expected cache contexts found without user toolbar tab.');
+    $this->assertToolbarCacheContexts(['user.permissions', 'route'], 'Expected cache contexts found without user toolbar tab.');
 
     // Test with the toolbar and contextual enabled.
     $this->installExtraModules(['contextual']);
     $this->adminUser2 = $this->drupalCreateUser(array_merge($this->perms, ['access contextual links']));
-    $this->assertToolbarCacheContexts(['user.permissions'], 'Expected cache contexts found with contextual module enabled.');
+    $this->assertToolbarCacheContexts(['user.permissions', 'route'], 'Expected cache contexts found with contextual module enabled.');
     \Drupal::service('module_installer')->uninstall(['contextual']);
 
     // Test with the tour module enabled.
     $this->installExtraModules(['tour']);
     $this->adminUser2 = $this->drupalCreateUser(array_merge($this->perms, ['access tour']));
-    $this->assertToolbarCacheContexts(['user.permissions'], 'Expected cache contexts found with tour module enabled.');
+    $this->assertToolbarCacheContexts(['user.permissions', 'route'], 'Expected cache contexts found with tour module enabled.');
     \Drupal::service('module_installer')->uninstall(['tour']);
   }