A patient interface assembly comprising a patient interface 12 and a connector 14 for connecting patient interface 12 to a conduit 16 thats joined to the connector 14 in a non-releasable manner. Patient interface 12 comprises a first connection formation and connector 14 comprises a second connection formation. Patient interface 12 and connector 14 are connectable in a connected configuration, wherein the first connection formation 26 and the second connection formation engage with a snap fit providing a non-releasable connection. The first connection formation may comprise a shoulder 26 having an abutment surface and at least a portion of the first and/or second connection formation is resiliently deformable allowing the second connection formation to engage the abutment surface with a snap-fit in the connected configuration. The connection may be releasable only upon applying force exceeding a predetermined threshold along an axis of engagement between patient interface 12 and connector 14. Second connection formation may comprise at least one projection 30,32 extending outwardly from a main body and/or arm of connector 14. Patient interface 12 and/or connector 14 may comprises a stop preventing over insertion of connector 14 into patient interface 12. Patient interface 12 may comprise an oxygen delivery mask.
