A respiratory mask assembly (10) for delivering breathable gas to a patient includes a frame (12) and a cushion (14). The cushion has a non-face contacting portion (24) structured to be connected to the frame, a face-contacting portion (26) structured to engage the patient's face, and a central portion (28) that interconnects the non-face contacting portion and the face contacting portion. The frame may be structured to allow a forehead support to assume multiple positions (30, 32), to compensate for replacement cushions that may have a different profile, shape or size. The cushion is structured to compensate for variations in strap tension, treatment pressure and/or movement of the patient. Headgear may be provided with a strap assembly in which one or more straps is provided with selectively adjustable elasticity or extensibility that may be automatically changed in dependence of treatment pressure and/or treatment type.