An anti-drainback valve contains a locking mechanism for securing the valve into to a filter assembly. The locking mechanism is made up of at least two keys that extend from the valve into beyond a cap of the filter assembly in order to secure the valve within the filter assembly. When multiple keys are employed, such keys may be equally spaced around the circumference of the cap. Manufacturing costs are kept minimal as minimal material is required and a two part mold may be employed during manufacturing.