diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index 8a753a1dad..ea9d3f93a4 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -1454,13 +1454,18 @@ if ( !function_exists( 'get_avatar' ) ) :
  * @param int|string|object $id_or_email A user ID,  email address, or comment object
  * @param int $size Size of the avatar image
  * @param string $default URL to a default image to use if no avatar is available
- * @param string $alt Alternate text to use in image tag
+ * @param string $alt Alternate text to use in image tag, the default is Avatar
  * @return string <img> tag for the user's avatar
 */
-function get_avatar( $id_or_email, $size = '96', $default = '', $alt = 'Avatar' ) {
+function get_avatar( $id_or_email, $size = '96', $default = '', $alt = false ) {
 	if ( ! get_option('show_avatars') )
 		return false;
 
+	if ( false === $alt)
+		$alt = __( 'Avatar' );
+
+	$safe_alt = attribute_escape( $alt );
+
 	if ( !is_numeric($size) )
 		$size = '96';
 
@@ -1517,9 +1522,9 @@ function get_avatar( $id_or_email, $size = '96', $default = '', $alt = 'Avatar'
 		if ( !empty( $rating ) )
 			$out .= "&amp;r={$rating}";
 
-		$avatar = "<img alt='{$alt}' src='{$out}' class='avatar avatar-{$size}' height='{$size}' width='{$size}' />";
+		$avatar = "<img alt='{$safe_alt}' src='{$out}' class='avatar avatar-{$size}' height='{$size}' width='{$size}' />";
 	} else {
-		$avatar = "<img alt='{$alt}' src='{$default}' class='avatar avatar-{$size} avatar-default' height='{$size}' width='{$size}' />";
+		$avatar = "<img alt='{$safe_alt}' src='{$default}' class='avatar avatar-{$size} avatar-default' height='{$size}' width='{$size}' />";
 	}
 
 	return apply_filters('get_avatar', $avatar, $id_or_email, $size, $default, $alt);