diff --git a/core/modules/system/core.api.php b/core/modules/system/core.api.php
index ff0ee61450155f1603c47b7062d4214d5aa2ffd9..ddd49744f0f320106cd38d08442b6f05fbfb7c24 100644
--- a/core/modules/system/core.api.php
+++ b/core/modules/system/core.api.php
@@ -550,11 +550,10 @@
  * appropriately for their particular sites.
  *
  * @section sec_define Defining permissions
- * Modules define permissions via a $module.permissions.yml file or by
- * implementing hook_permission(). The return value defines machine names,
- * human-readable names, and optionally descriptions for each permission type.
- * The machine names are the canonical way to refer to permissions for access
- * checking.
+ * Modules define permissions via a $module.permissions.yml file. The return
+ * value defines machine names, human-readable names, and optionally
+ * descriptions for each permission type. The machine names are the canonical
+ * way to refer to permissions for access checking.
  *
  * @section sec_access Access permission checking
  * Depending on the situation, there are several methods for ensuring that
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index b859a2803efd10928de7221f2477ef56ef14b67c..ae416ed556bc0d91f0513802007a243faaceeb04 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -942,55 +942,6 @@ function hook_system_info_alter(array &$info, \Drupal\Core\Extension\Extension $
   }
 }
 
-/**
- * Define user permissions.
- *
- * This hook can supply permissions that the module defines, so that they
- * can be selected on the user permissions page and used to grant or restrict
- * access to actions the module performs.
- *
- * Permissions are checked using \Drupal::currentUser()->hasPermission().
- *
- * For a detailed usage example, see page_example.module.
- *
- * @return
- *   An array whose keys are permission names and whose corresponding values
- *   are arrays containing the following key-value pairs:
- *   - title: The human-readable name of the permission, to be shown on the
- *     permission administration page. This should be wrapped in the t()
- *     function so it can be translated.
- *   - description: (optional) A description of what the permission does. This
- *     should be wrapped in the t() function so it can be translated.
- *   - restrict access: (optional) A boolean which can be set to TRUE to
- *     indicate that site administrators should restrict access to this
- *     permission to trusted users. This should be used for permissions that
- *     have inherent security risks across a variety of potential use cases
- *     (for example, the "administer filters" and "bypass node access"
- *     permissions provided by Drupal core). When set to TRUE, a standard
- *     warning message defined in user_admin_permissions() will be displayed
- *     with the permission on the permission administration page. Defaults
- *     to FALSE.
- *   - warning: (optional) A translated warning message to display for this
- *     permission on the permission administration page. This warning overrides
- *     the automatic warning generated by 'restrict access' being set to TRUE.
- *     This should rarely be used, since it is important for all permissions to
- *     have a clear, consistent security warning that is the same across the
- *     site. Use the 'description' key instead to provide any information that
- *     is specific to the permission you are defining.
- *
- * @ingroup user_api
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
- *   Use $module.permissions.yml files.
- */
-function hook_permission() {
-  return array(
-    'administer my module' =>  array(
-      'title' => t('Administer my module'),
-      'description' => t('Perform administration tasks for my module.'),
-    ),
-  );
-}
-
 /**
  * Provide online user help.
  *
diff --git a/core/modules/user/src/Access/PermissionAccessCheck.php b/core/modules/user/src/Access/PermissionAccessCheck.php
index 6d1010172cd27182b23cfa7358a2916f8433b65e..70c99db06b044cb25a0c18df3d940a1a91e6c72d 100644
--- a/core/modules/user/src/Access/PermissionAccessCheck.php
+++ b/core/modules/user/src/Access/PermissionAccessCheck.php
@@ -13,7 +13,8 @@
 use Symfony\Component\Routing\Route;
 
 /**
- * Determines access to routes based on permissions defined via permissions.yml.
+ * Determines access to routes based on permissions defined via
+ * $module.permissions.yml files.
  */
 class PermissionAccessCheck implements AccessInterface {
 
diff --git a/core/modules/user/src/PermissionHandler.php b/core/modules/user/src/PermissionHandler.php
index 36a67571b444f73f067e9da93b11be1e1707b0a5..0ec4eeeee5dd062d9716368e6868c15b8b803de3 100644
--- a/core/modules/user/src/PermissionHandler.php
+++ b/core/modules/user/src/PermissionHandler.php
@@ -14,18 +14,16 @@
 use Drupal\Core\StringTranslation\TranslationInterface;
 
 /**
- * Provides the available permissions based on hook_permission and yml files.
+ * Provides the available permissions based on yml files.
  *
  * To define permissions you can use a $module.permissions.yml file:
  *
  * @code
- * 'access all views':
+ * access all views:
  *   title: 'Bypass views access control'
  *   description: 'Bypass access control when accessing views.'
- *   'restrict access': TRUE
- * @encode
- *
- * @see hook_permission()
+ *   restrict access: true
+ * @endcode
  */
 class PermissionHandler implements PermissionHandlerInterface {
 
@@ -89,8 +87,6 @@ protected function getYamlDiscovery() {
   public function getPermissions() {
     $all_permissions = $this->buildPermissionsYaml();
 
-    $all_permissions += $this->buildPermissionsModules();
-
     return $this->sortPermissions($all_permissions);
   }
 
@@ -170,33 +166,6 @@ protected function buildPermissionsYaml() {
     return $all_permissions + $all_callback_permissions;
   }
 
-  /**
-   * Builds all permissions provided by .module files.
-   *
-   * @return array[]
-   *   Each return permission is an array with the following keys:
-   *   - title: The title of the permission.
-   *   - description: The description of the permission, defaults to NULL.
-   *   - provider: The provider of the permission.
-   */
-  protected function buildPermissionsModules() {
-    $all_permissions = array();
-    foreach ($this->moduleHandler->getImplementations('permission') as $provider) {
-      $permissions = $this->moduleHandler->invoke($provider, 'permission');
-      foreach ($permissions as &$permission) {
-        if (!is_array($permission)) {
-          $permission = array(
-            'title' => $permission,
-            'description' => NULL,
-          );
-        }
-        $permission['provider'] = $provider;
-      }
-      $all_permissions += $permissions;
-    }
-    return $all_permissions;
-  }
-
   /**
    * Sorts the given permissions by provider name and title.
    *
diff --git a/core/modules/user/tests/src/Unit/PermissionHandlerTest.php b/core/modules/user/tests/src/Unit/PermissionHandlerTest.php
index 013986dd2e7598b9e5ea9470f65abea049a8c3a5..858b8d6f45929f3bf9c3ca50ff55fab15927f115 100644
--- a/core/modules/user/tests/src/Unit/PermissionHandlerTest.php
+++ b/core/modules/user/tests/src/Unit/PermissionHandlerTest.php
@@ -76,63 +76,6 @@ protected function mockModuleExtension($module, $name) {
     return $extension;
   }
 
-  /**
-   * Tests permissions by hook_permission.
-   *
-   * @covers ::__construct
-   * @covers ::getPermissions
-   * @covers ::buildPermissions
-   * @covers ::buildPermissionsModules
-   * @covers ::sortPermissions
-   * @covers ::getModuleNames
-   */
-  public function testBuildPermissionsModules() {
-    $modules = array('module_a', 'module_b', 'module_c');
-    $extensions = array(
-      'module_a' => $this->mockModuleExtension('module_a', 'Module a'),
-      'module_b' => $this->mockModuleExtension('module_b', 'Moduleb'),
-      'module_c' => $this->mockModuleExtension('module_c', 'Module c'),
-    );
-    $permissions = array(
-      'module_a' => array('access_module_a' => 'single_description'),
-      'module_b' => array('access module b' => array('title' => 'Access B', 'description' => 'bla bla')),
-      'module_c' => array('access_module_c' => array('title' => 'Access C', 'description' => 'bla bla', 'restrict access' => TRUE)),
-    );
-    $this->moduleHandler = $this->getMock('Drupal\Core\Extension\ModuleHandlerInterface');
-    $this->moduleHandler->expects($this->once())
-      ->method('getModuleDirectories')
-      ->willReturn([]);
-
-    $this->moduleHandler->expects($this->at(1))
-      ->method('getImplementations')
-      ->with('permission')
-      ->willReturn($modules);
-
-    // Setup the module handler.
-    $i = 2;
-    foreach ($modules as $module_name) {
-      $this->moduleHandler->expects($this->at($i++))
-        ->method('invoke')
-        ->with($module_name)
-        ->willReturn($permissions[$module_name]);
-    }
-    $this->moduleHandler->expects($this->any())
-      ->method('getModuleList')
-      ->willReturn(array_flip($modules));
-
-    $this->permissionHandler = new TestPermissionHandler($this->moduleHandler, $this->stringTranslation, $this->controllerResolver);
-
-    // Setup system_rebuild_module_data().
-    $this->permissionHandler->setSystemRebuildModuleData($extensions);
-
-    $actual_permissions = $this->permissionHandler->getPermissions();
-    $this->assertPermissions($actual_permissions);
-    // Ensure that the human name of the module is taken into account for the
-    // sorting.
-    $this->assertSame(array('access_module_a', 'access_module_c', 'access module b'), array_keys($actual_permissions));
-  }
-
-
   /**
    * Tests permissions provided by YML files.
    *