Abstract: A self-locking hinge is disclosed for pivotally attaching a door to a frame member. The hinge includes first and second hinge members which are pivotally joined together by a pin. A socket is formed in the first hinge member which is designed to receive a detent mechanism. The detent mechanism has at least one tooth formed on its lower surface which will engage a complimentary notch formed on the upper surface of the second hinge member upon rotation of the first hinge member relative to the second hinge member. The tooth and notch are so configured as to permit rotation of the first hinge member in one direction but will prevent its rotation in an opposite direction once the tooth has engaged the notch. A spring is positioned located within the socket of the first hinge member so as to bias the detent downward towards the second hinge member.