diff --git a/core/modules/user/src/Tests/UserTemplateSuggestionsTest.php b/core/modules/user/src/Tests/UserTemplateSuggestionsTest.php
new file mode 100644
index 0000000..e23e401
--- /dev/null
+++ b/core/modules/user/src/Tests/UserTemplateSuggestionsTest.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Drupal\user\Tests;
+
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests user template suggestions.
+ *
+ * @group user
+ */
+class UserTemplateSuggestionsTest extends WebTestBase {
+
+  /**
+   * Tests if user_theme_suggestions_user() generates the correct suggestions.
+   */
+  public function testUserThemeHookSuggestions() {
+    // Create user to be rendered.
+    $user = $this->drupalCreateUser();
+
+    // Set the view mode.
+    $view_mode = 'user.my_custom_view_mode';
+    $build = \Drupal::entityTypeManager()->getViewBuilder('user')->view($user, $view_mode);
+
+    $variables['elements'] = $build;
+    $suggestions = \Drupal::moduleHandler()->invokeAll('theme_suggestions_user', [$variables]);
+    $this->assertEqual($suggestions, ['user__user_my_custom_view_mode'], 'Found expected user template suggestions.');
+  }
+
+}
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 90b813f..dbdfd14 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -1424,3 +1424,13 @@ function template_preprocess_user(&$variables) {
     $variables['content'][$key] = $variables['elements'][$key];
   }
 }
+
+/**
+ * Implements hook_theme_suggestions_HOOK().
+ */
+function user_theme_suggestions_user(array $variables) {
+  $suggestions = [];
+  $sanitized_view_mode = strtr($variables['elements']['#view_mode'], '.', '_');
+  $suggestions[] = 'user__' . $sanitized_view_mode;
+  return $suggestions;
+}