An undersea hydraulic coupling having a ring-shaped metal seal that is held in place between the female member body and a sleeve-shaped seal retainer is disclosed. The annular metal seal includes a lip or leg section which is clamped in place between the female member body and the seal retainer. A hollow portion of the seal extends radially inwardly from the lip portion of the seal and is expansible to form a fluid tight seal against the body of the male member. The hollow portion of the metal seal is preferably cylindrical in cross-section and is sufficiently flexible in response to fluid pressure to form a fluid tight seal between the female member, male member, and seal retainer.