Abstract: An actuator for a plug valve of the type having a body with a central chamber having diametrically opposed inlet and outlet ports and a plug within the chamber having a transverse passage therethrough and an upstanding stem. The plug has a first, upper, valve-open position with its transverse passage in alignment with the inlet and outlet ports of the chamber, and a second, lower valve-closed position wherein its transverse passage is oriented at 90.degree. to the chamber inlet and outlet ports and seal means on the plug are in sealing engagement with the chamber walls about the inlet and outlet ports. The top of the chamber is closed by a bonnet having a packing gland through which the plug stem extends. The actuator comprises a hollow cylindrical yoke, the lower end of which is affixed to the bonnet with the plug stem extending into the yoke. The upper end of the yoke is provided with a bearing cap.