A cushion assembly (3105, 5105, 6105, 7105, 8105, 9105, 14105, 16175, 27105, 28105, 29105, 30105, 31105) for interfacing with a patient's airways including at least the patient's nares, the cushion assembly being configured to maintain a therapy pressure above ambient air pressure in use, throughout a patient's respiratory cycle, while the patient is sleeping, to ameliorate sleep disordered breathing, said cushion assembly comprising: a plenum chamber (3200, 10200, 11200, 13200, 14200, 30200, 31200) at least partially forming a cavity pressurisable to a therapeutic pressure of at least 6 cmH 2 O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient; and a seal-forming structure (8100, 9100) having a textile membrane (10130, 32130) constructed and arranged to form a pressure-assisted seal with a region of the patient's face surrounding an entrance to the patient's airways inferior to a nasal bridge region of the patient's face, said textile membrane having a hole formed therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient's nares, the seal-forming structure (8100, 9100) constructed and arranged to maintain said therapeutic pressure in the cavity throughout the patient's respiratory cycle in use, the seal-forming structure including a flexible support structure (3120, 6120, 7120, 8120, 9120, 10120, 14120, 29120, 30120, 31120) to support the textile membrane (10130, 32130), the support structure being connected to the plenum chamber (3200, 10200, 11200, 13200, 14200, 30200, 31200), wherein the support structure (3120, 6120, 7120, 8120, 9120, 10120, 14120, 29120, 30120, 31120) is overmolded onto the textile membrane (10130, 32130), the textile membrane being attached to the support structure along an outer perimeter of the textile membrane such that textile membrane extends radially inwardly beyond the support structure, wherein the textile membrane (10130, 32130) includes a textile material adapted to contact the patient's face and an air impermeable silicone layer applied thereto, the textile material comprising 1) nylon and/or polyester, and 2) elastane, wherein a yarn count of the nylon and/or polyester is in a range of 20-80 denier, wherein the textile membrane (10130, 32130) has stretchability in both a direction of the wales and a direction of the course, and the air impermeable silicone layer facilitates the stretchability of the textile membrane (10130, 32130), and wherein a thickness of the air impermeable silicone layer is in the range of 0.04mm to 0.125mm. a plenum chamber (3200, 10200, 11200, 13200, 14200, 30200, 31200) at least partially forming a cavity pressurisable to a therapeutic pressure of at least 6 cmH 2 O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient; and a seal-forming structure (8100, 9100) having a textile membrane (10130, 32130) constructed and arranged to form a pressure-assisted seal with a region of the patient's face surrounding an entrance to the patient's airways inferior to a nasal bridge region of the patient's face, said textile membrane having a hole formed therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient's nares, the seal-forming structure (8100, 9100) constructed and arranged to maintain said therapeutic pressure in the cavity throughout the patient's respiratory cycle in use, the seal-forming structure including a flexible support structure (3120, 6120, 7120, 8120, 9120, 10120, 14120, 29120, 30120, 31120) to support the textile membrane (10130, 32130), the support structure being connected to the plenum chamber (3200, 10200, 11200, 13200, 14200, 30200, 31200), wherein the support structure (3120, 6120, 7120, 8120, 9120, 10120, 14120, 29120, 30120, 31120) is overmolded onto the textile membrane (10130, 32130), the textile membrane being attached to the support structure along an outer perimeter of the textile membrane such that textile membrane extends radially inwardly beyond the support structure, wherein the textile membrane (10130, 32130) includes a textile material adapted to contact the patient's face and an air impermeable silicone layer applied thereto, the textile material comprising 1) nylon and/or polyester, and 2) elastane, wherein a yarn count of the nylon and/or polyester is in a range of 20-80 denier, wherein the textile membrane (10130, 32130) has stretchability in both a direction of the wales and a direction of the course, and the air impermeable silicone layer facilitates the stretchability of the textile membrane (10130, 32130), and wherein a thickness of the air impermeable silicone layer is in the range of 0.04mm to 0.125mm.