A nasal mask assembly includes a relatively flexible cushion arrangement including a cushion that provides a breathing chamber and a face-contacting portion to form a seal around the patient's nose in use, an inlet tube supported by the cushion to deliver breathable gas into the breathing chamber for breathing by the patient, and three support members extending outwardly from the cushion. A relatively rigid frame is provided to a front side of the cushion arrangement. The frame includes three headgear attachment structures. Headgear includes three headgear straps engagable with the three support members and the three headgear attachment structures to maintain the cushion arrangement in a desired position on the patient's face.