diff --git src/wp-includes/shortcodes.php src/wp-includes/shortcodes.php
index 47cb57a..6b3e5a3 100644
--- src/wp-includes/shortcodes.php
+++ src/wp-includes/shortcodes.php
@@ -305,7 +305,7 @@ function do_shortcode_tag( $m ) {
  */
 function shortcode_parse_atts($text) {
 	$atts = array();
-	$pattern = '/(\w+)\s*=\s*"([^"]*)"(?:\s|$)|(\w+)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/';
+	$pattern = '/(\w+(?:\-\w+)*)\s*=\s*"([^"]*)"(?:\s|$)|(\w+(?:\-\w+)*)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+(?:\-\w+)*)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/';
 	$text = preg_replace("/[\x{00a0}\x{200b}]+/u", " ", $text);
 	if ( preg_match_all($pattern, $text, $match, PREG_SET_ORDER) ) {
 		foreach ($match as $m) {