diff --git a/wp-includes/ms-default-constants.php b/wp-includes/ms-default-constants.php
index 2a193afa98..53dfc9b55c 100644
--- a/wp-includes/ms-default-constants.php
+++ b/wp-includes/ms-default-constants.php
@@ -63,7 +63,7 @@ function ms_cookie_constants(  ) {
 	 * @since 2.6.0
 	 */
 	if ( !defined( 'ADMIN_COOKIE_PATH' ) ) {
-		if( !is_subdomain_install() ) {
+		if ( ! is_subdomain_install() || trim( parse_url( get_option( 'siteurl' ), PHP_URL_PATH ), '/' ) ) {
 			define( 'ADMIN_COOKIE_PATH', SITECOOKIEPATH );
 		} else {
 			define( 'ADMIN_COOKIE_PATH', SITECOOKIEPATH . 'wp-admin' );