diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index b9f13face0d4..0754dabb8f64 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -321,6 +321,7 @@
 			'style' => true,
 			'xml:lang' => true,
 		),
+		'small' => array(),
 		'strike' => array(),
 		'strong' => array(),
 		'sub' => array(),