Reference external file as a function
You can’t. Create a function that loads that file: function load_admin_page_file() { require ‘admin-members.php’; } Then use that function name as callback argument. In PHP 5.3 you can use a lambda: add_menu_page( ‘Members’, ‘Members’, ‘manage_options’, ‘members’, function() { require ‘admin-members.php’; } );