Headgear configured to be secured to a patient interface of a respiratory therapy system, to mount the patient interface on a user's head, the headgear comprising; two pairs of side straps (5A, 5B), including an upper pair of side straps and a lower pair of side straps, each side strap of each pair 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 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 of the upper pair being joined to a respective arm of the rear panel and connected entirely to the respective arm of the rear panel in an upper corner region of the rear panel, the second end of each side strap of the lower pair being connected to a lower corner area of the rear panel, the lower corner area including at least a portion of the respective arm and the main body, wherein the upper side straps and the lower side straps are inclined towards each other at their first ends; 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 laterally extending arm being inclined upwardly away from the main body and away from the central longitudinal axis, extending outwardly from the central longitudinal axis 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; characterised in that 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. two pairs of side straps (5A, 5B), including an upper pair of side straps and a lower pair of side straps, each side strap of each pair 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 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 of the upper pair being joined to a respective arm of the rear panel and connected entirely to the respective arm of the rear panel in an upper corner region of the rear panel, the second end of each side strap of the lower pair being connected to a lower corner area of the rear panel, the lower corner area including at least a portion of the respective arm and the main body, wherein the upper side straps and the lower side straps are inclined towards each other at their first ends; 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; 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 laterally extending arm being inclined upwardly away from the main body and away from the central longitudinal axis, extending outwardly from the central longitudinal axis 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; characterised in that 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.