A respiratory mask assembly for delivering breathable gas to a patient includes a frame having a main body and a side frame member provided on each lateral side of the main body. The main body provides an orifice therethrough for the introduction of breathable gas into a nasal breathing cavity and a collar that substantially surrounds the orifice. At least one of the side frame members includes an integrally formed locking clip receiver assembly. The frame is formed by molding such that mold components of a mold can be withdrawn along a single plane to separate the mold from the collar and the locking clip receiver assembly.