Abstract: A sliding-sleeve valve for an oil well comprises a valve body provided with ports for the passage of fluid therethrough, and a longitudinally slidable sleeve for opening and closing the ports. The sleeve is located on the outside of the valve body and provided internally with drive teeth which are accessible from within the valve body through an orifice in the valve body. The sleeve is moved by an engagement and drive member carried by an actuating tool which is lowered into the valve body. The engagement and drive member is housed in a bush of the tool and caused to project through an orifice in the bush and into engagement with the drive teeth of the sleeve by ramp means during longitudinal displacement of an actuating rod of the tool.