Abstract: An adjustable ratchet wrench has a housing carried by a handle. The housing has a generally cylindrical chamber which carries a control member which in turn supports the jaws. The control member is connected to the handle by a ratchet assembly whose setting determines the direction in which the tool may be used to turn a workpiece. The housing also carries a cam disk that engages the jaws and opens and closes them depending upon the direction in which it is rotated. A locking mechanism is provided to prevent the jaws fro opening after they have been adjusted to grip a particular workpiece in response to reactive forces on the jaws. The wrench may also have a powered handle to drive the workpiece.