A cushion for a full facial respiratory mask assembly includes a frame-connecting portion, a face-contacting portion, and a gusset portion disposed between and joining the frame-connecting and face-contacting portions. The gusset portion is structured to allow relative movement of a mask frame to occur towards and away from a patient's face, and the gusset portion includes a nasal bridge perimetrical region, a mouth perimetrical region and a transition perimetrical region. The nasal bridge perimetrical region includes a w-shaped or concertina-type fold having little or no projected area relative to the face-contacting portion of the cushion. The mouth perimetrical region extends laterally outwardly to form an increased projected area relative to the face-contacting portion of the cushion. The transition perimetrical region extends laterally outwardly an amount intermediate of the nasal bridge perimetrical region and the mouth perimetrical region.