Index: src/wp-includes/general-template.php
===================================================================
--- src/wp-includes/general-template.php	(revision 39474)
+++ src/wp-includes/general-template.php	(working copy)
@@ -357,7 +357,14 @@
  *
  * @return string User registration URL.
  */
-function wp_registration_url() {
+function wp_registration_url($redirect = '') {
+	$args = array( 'action' => 'register' );
+	if ( !empty($redirect) ) {
+		$args['redirect_to'] = urlencode( $redirect );
+	}
+
+	$registration_url = add_query_arg($args, site_url('wp-login.php', 'login'));
+
 	/**
 	 * Filters the user registration URL.
 	 *
@@ -365,7 +372,7 @@
 	 *
 	 * @param string $register The user registration URL.
 	 */
-	return apply_filters( 'register_url', site_url( 'wp-login.php?action=register', 'login' ) );
+	return apply_filters( 'register_url', $registration_url, $redirect );
 }
 
 /**