diff --git a/wp-admin/admin-header.php b/wp-admin/admin-header.php
index e0a4241844..b8b9f10517 100644
--- a/wp-admin/admin-header.php
+++ b/wp-admin/admin-header.php
@@ -10,6 +10,10 @@
 if ( ! defined( 'WP_ADMIN' ) )
 	require_once( './admin.php' );
 
+// In case admin-header.php is included in a function.
+global $title, $hook_suffix, $current_screen, $wp_locale, $pagenow, $wp_version, $is_iphone,
+	$user_identity, $current_site, $update_title, $total_update_count, $parent_file;
+
 get_admin_page_title();
 $title = esc_html( strip_tags( $title ) );