A strap fastener for a motorcycle helmet is constructed of a unitary jacket that defines a hollow shell and latch tripping lever arms. A latching fork has a pair of resilient, generally parallel legs and can be slipped through a fabric loop which is attached to one side of the helmet. A fabric strap, secured to the other side of the helmet, is threaded through slots in a catch. The fork and catch are inserted into the jacket shell from opposite longitudinal directions. As the catch approaches the tips of the legs of the fork within the enclosure of the shell, it deflects feet defined upon the legs, overcoming the spring bias of the legs. When the catch is fully inserted, the feet of the fork legs spring back and engage hooks on the catch. The fork and the catch can be disengaged by depression of the lever arms on the jacket. The lever arms act through transverse apertures in the jacket. The lever arms act through transverse apertures in the jacket shell to overcome the spring bias of the legs to disengage the feet of the fork legs from the hooks on the catch.