Abstract: A rapid engagement/release coupling having a female connector, a male connector, and a retaining ring. The female connector having an insertion end, a cylindrical sealing portion, and an annular groove having a first stop surface. The male connector carrying a sealing ring configured to cooperate with the cylindrical sealing portion and having a recessed annular portion having a second stop surface. The retaining ring having a collar and a tubular portion equipped with a plurality of longitudinal splits which divide the tubular portion into a plurality of sectors. The sectors having teeth configured to engage the annular groove, wherein the teeth have outer conical surfaces and inner conical surfaces. The inner and outer conical surfaces of the teeth having different inclination angles with respect to a longitudinal axis. The inclination angle of the outer conical surfaces is greater than the inclination angle of the inner conical surfaces.