diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 58a7742228..d82bf97164 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -3603,7 +3603,7 @@ function wp_allowed_protocols() {
 	static $protocols;
 
 	if ( empty( $protocols ) ) {
-		$protocols = array( 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet', 'mms', 'rtsp', 'svn', 'tel', 'fax' );
+		$protocols = array( 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet', 'mms', 'rtsp', 'svn', 'tel', 'fax', 'xmpp' );
 		$protocols = apply_filters( 'kses_allowed_protocols', $protocols );
 	}