A coupler for coupling implements having a first connecting pin and a second connecting pin, to a vehicle, for example, to the arm of an excavator. The coupler has a body component that is connectable to the vehicle, and which includes a forward recess for receiving the first connecting pin. The coupler also includes a movable component which is supported by the body component and which has an aft jaw or recess for receiving the second connecting pin and is movable through a range of travel relative to the body component. The movable component includes a rear locking member which is movable between an extended position in which the rear locking member can prevent the second connecting pin from exiting the aft recess and a retracted position in which the rear locking member can allow the second connecting pin to exit the aft recess.