Abstract: A rotary valve with a latching/locking operating handle assembly includes a valve body carrying a rotary valve element having an outwardly extending valve stem. A main handle body is joined to the stem and provides guide grooves for cooperating first and second operating members connected by a cam assembly such that selective horizontal movement of the first operating member produces vertical movement of the second operating member. A latch pin carried by the second member is thereby caused to move between engaged and disengaged positions with the valve body.