A headgear for use with a mask includes a first strap being configured to engage a back of a patient's head and extend on either side of the patient's parietal bone behind the patient's ears and assume, in use, a substantially circular or oval shape. At least a portion of the first strap is substantially inextensible. The headgear also includes at least one second strap configured to removably connect the first strap to the mask. The second strap may be more extensible than the first strap. At least a portion of the first strap is self-supporting such that the headgear maintains a three dimensional shape when not in use. The substantially inextensible portion of the first strap is constructed to resiliently return to a predetermined shape when not in use. The arcuate region includes a first portion that may be arranged to align substantially parallel with a top of the patient's head and a second portion being arranged to align substantially to a rear surface of the patient's head.