An air release valve which includes a housing, an inlet, an outlet, a valve seat, a buoyant closure member and a variable throttle arrangement is provided. The housing defines a chamber and the buoyant closure member is positioned in the chamber and is displaceable between a lower position in which it is clear of the valve seat and permits the flow of fluid through the chamber and an upper position in which it seats sealingly against the valve seat to interrupt the flow of fluid through the chamber, the closure member being displaced, in use, from its lower position to its raised position by the buoyant forces acting thereon as a result of the entry of liquid into the chamber through the inlet. The throttle arrangement is configured to throttle air flow and inhibit premature closing of the closure member.