A wound retractor (320) comprises a distal ring (3) for insertion through a wound opening (6), a proximal ring (4) for location externally of the wound opening (6), a valve (10) mounted to the proximal ring (4), and a sleeve (2) for retracting laterally the sides of the wound opening (6). The wound retractor (320) also comprises a flexible release member (81) for releasing the distal ring (3) from a retracting configuration for removal of the distal ring (3) from the wound opening (6). A first end (301) of the release member (81) is attached to the valve housing (102), the release member (81) loops around the distal ring (3), and a second end (302) of the release member (81) is movable relative to the proximal ring (4) to release the distal ring (3) from the retracting configuration.