Headgear configured to be secured to a patient interface of a respiratory therapy system, to mount the patient interface on a user's head, comprises； at least one pair of side straps, each side strap having first and second opposed ends, a first end of each strap being secured to, or being configured to be secured to, the patient interface and to extend along the sides of the user's head； a rear panel configured to engage the rear of the user's head, the second end of each side strap being joined to the rear panel such that the or each pair of side straps extend from the rear panel； wherein the rear panel comprises a main body and a pair of laterally extending arms, the second end of each side strap being joined to a respective arm； the main body comprising: opposed top and base margins which are spaced apart by a distance, opposed side margins extending between the top and base margins, and a central longitudinal axis bisecting the top and base margins； each arm being inclined relative to the central longitudinal axis, extending away from a respective side margin of the main body and comprising a distal arm end, each distal arm end having a width measured in a direction substantially parallel with the central longitudinal axis； wherein the width of each distal arm end is between 30% to 60% of the distance between the opposed top and base margins of the main body.
