diff --git a/phpBB/includes/functions_validate.php b/phpBB/includes/functions_validate.php
index 1cc166c66f..898c2401a6 100644
--- a/phpBB/includes/functions_validate.php
+++ b/phpBB/includes/functions_validate.php
@@ -121,7 +121,7 @@ function validate_email($email)
 
 	if ($email != '')
 	{
-		if (preg_match('/^[a-z0-9&.-_+]+@[a-z0-9\-]+\.([a-z0-9\-]+\.)*?[a-z]+$/is', $email))
+		if (preg_match('/^[a-z0-9&\'\.\-_\+]+@[a-z0-9\-]+\.([a-z0-9\-]+\.)*?[a-z]+$/is', $email))
 		{
 			$sql = "SELECT ban_email
 				FROM " . BANLIST_TABLE;