diff --git a/wp-admin/admin-ajax.php b/wp-admin/admin-ajax.php
index 28ba8b9009..b2f3541743 100644
--- a/wp-admin/admin-ajax.php
+++ b/wp-admin/admin-ajax.php
@@ -30,6 +30,8 @@ require_once( ABSPATH . 'wp-admin/includes/admin.php' );
 require_once( ABSPATH . 'wp-admin/includes/ajax-actions.php' );
 
 @header( 'Content-Type: text/html; charset=' . get_option( 'blog_charset' ) );
+@header( 'X-Robots-Tag: noindex' );
+
 send_nosniff_header();
 
 do_action( 'admin_init' );