A hydraulic valve coupling has an interlock mechanism that includes at least one blocking member located within an interlock passage of a body portion of the valve coupling. The interlock passage has a first end opening to the valve shaft and a second end opening to an interface groove of the valve coupling. The at least one blocking member can be retracted within the interlock passage such that the valve coupling can be rotated and disengaged from a mating coupling. When the valve is in the open position, the at least one blocking member is positioned within the interlock passage such that it contacts the mating coupling and prevents rotation of the valve coupling relative to the mating coupling. The second end of the at least one blocking member can be shaped such that it is retracted as a result of contact with the mating coupling and without the assistance of a biasing mechanism.