Disable Admin Bar for All Users Except for Administrators

To disable admin bar for all groups of users except admin, just paste the following code in your theme’s functions.php file.

add_action('after_setup_theme', 'remove_admin_bar');

function remove_admin_bar() {
if (!current_user_can('administrator') && !is_admin()) {
  show_admin_bar(false);
}
}

easy-peasy ;)