There is provided a respiratory mask (10；100；200) for delivering an inhalation gas to the airways of a wearer, the respiratory mask comprising a body (10) of generally concave shape and having a peripheral edge, the body being adapted to provide a cavity (11,12) in use about the mouth and nose of a wearer such that the inhalation gas can be inhaled by the wearer from the cavity. The body has an inlet port (13) that is engageable with a supply of inhalation gas and in communication with the cavity. The respiratory mask includes a resilient seal formation (20) depending from at least a portion of the peripheral edge. The resilient seal formation comprises both an inwardly (22) and outwardly (28) depending lip portion relative to the peripheral edge of the body. The inwardly depending lip portion (22) is arranged in use to pass closely beneath the mandible of a wearer (38) having a relatively smaller facial dimension (Y) and the outwardly depending lip portion (28) is arranged to pass closely beneath the mandible of a wearer (42) having a relatively larger facial dimension (Y'). The mask may accommodate a range of facial dimensions whilst still retaining an effective seal.
