Abstract: A ball valve operator for a ball valve mounted in a pipe and having a control handle with a first position corresponding to the valve's normal position and a second position corresponding to the valve's actuated position. The ball valve operator includes a pneumatic cylinder mountable on the pipe, for driving a piston having a proximal and distal end. An adaptor plate is provided for attachment to the control handle by fastening means with the piston being rotatably fastened to the plate. An adjustment slot in the adaptor plate movably receives the fastening means and allows the fastening means to be selectively locked in place, so that the operator may be adjusted to move the handle through approximately its full range of motion without exceeding that range.