diff --git a/core/modules/system/lib/Drupal/system/Controller/SystemController.php b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
index d07752c..6a1626c 100644
--- a/core/modules/system/lib/Drupal/system/Controller/SystemController.php
+++ b/core/modules/system/lib/Drupal/system/Controller/SystemController.php
@@ -260,7 +260,7 @@ public function themesPage() {
               );
             }
             $theme->operations[] = array(
-              'title' => $this->t('Set default'),
+              'title' => $this->t('Set as default'),
               'route_name' => 'system.theme_set_default',
               'query' => $query,
               'attributes' => array('title' => $this->t('Set !theme as default theme', array('!theme' => $theme->info['name']))),
@@ -276,7 +276,7 @@ public function themesPage() {
             'attributes' => array('title' => $this->t('Enable !theme theme', array('!theme' => $theme->info['name']))),
           );
           $theme->operations[] = array(
-            'title' => $this->t('Enable and set default'),
+            'title' => $this->t('Enable and set as default'),
             'route_name' => 'system.theme_set_default',
             'query' => $query,
             'attributes' => array('title' => $this->t('Enable !theme as default theme', array('!theme' => $theme->info['name']))),
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
index 554450a..e220616 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/ThemeTest.php
@@ -235,7 +235,7 @@ function testSwitchDefaultTheme() {
     // Enable Bartik and set it as the default theme.
     theme_enable(array('bartik'));
     $this->drupalGet('admin/appearance');
-    $this->clickLink(t('Set default'));
+    $this->clickLink(t('Set as default'));
     $this->assertEqual(\Drupal::config('system.theme')->get('default'), 'bartik');
 
     drupal_flush_all_caches();
@@ -245,7 +245,7 @@ function testSwitchDefaultTheme() {
     $this->assertText('Bartik(' . t('active tab') . ')', 'Default local task on blocks admin page is the default theme.');
     // Switch back to Stark and test again to test that the menu cache is cleared.
     $this->drupalGet('admin/appearance');
-    $this->clickLink(t('Set default'), 0);
+    $this->clickLink(t('Set as default'), 0);
     $this->drupalGet('admin/structure/block');
     $this->assertText('Stark(' . t('active tab') . ')', 'Default local task on blocks admin page has changed.');
   }
diff --git a/core/modules/system/system.routing.yml b/core/modules/system/system.routing.yml
index 4d27aa6..d03034d 100644
--- a/core/modules/system/system.routing.yml
+++ b/core/modules/system/system.routing.yml
@@ -318,7 +318,7 @@ system.themes_page:
 system.theme_set_default:
   path: '/admin/appearance/default'
   defaults:
-    _title: 'Set default theme'
+    _title: 'Set as default theme'
     _content: '\Drupal\system\Controller\SystemController::themeSetDefault'
   requirements:
     _permission: 'administer themes'