The present folding stock adapter can be used with many types of military-type assault rifles that typically comprise a receiver extension, buffer and action spring. The present folding stock adapter can be used to add a folding capability to a standard stock allowing it to fold against a rifle's receiver when the weapon is not in use, thus reducing the overall length of the weapon. This reduction in length can facilitate its maneuverability, storage and transport in cramped quarters. The present device can also allow for the quick unfolding of the stock in order to allow the weapon to function and be fired normally.