Disable WordPress Theme Changing

Add the following code to your WordPress theme’s function.php file, or a functionality plugin to prevent Users from changing the WordPress theme in the Dashboard.

add_action( 'admin_init', 'slt_lock_theme' );
function slt_lock_theme() {
	global $submenu, $userdata;
	get_currentuserinfo();
	if ( $userdata->ID != 1 ) {
		unset( $submenu['themes.php'][5] );
		unset( $submenu['themes.php'][15] );
	}
}