A respiratory mask assembly for delivering breathable gas to a patient includes a frame and at least one locking clip. The frame has a main body and a side frame member provided on each lateral side of the main body, at least one of the side frame members including a locking clip receiver assembly. The at least one locking clip has a main body providing a front portion adapted to be removably coupled with the at least one locking clip receiver assembly and a rear portion adapted to be removably coupled to a headgear assembly. The rear portion includes a cross bar that forms an opening through which a strap of the headgear assembly can pass and be removably coupled with the cross bar, and the front portion includes at least one resiliently flexible spring arm that is flexible within the plane of the main body.