An improved two-part electrical connector of the interlocking type. A generally cylindrical plug unit having a plurality of male electrical contacts extending from a front face thereof is provided. A generally cylindrical socket unit is adapted for mating with a plug unit. The socket unit has a front face with slots therein and a plurality of female electrical contacts beneath the slots to receive the male electrical contacts when the units are mated. The socket unit includes means for locking the plug and socket units against axial disengagement when the mated units are twisted with respect to one another. A generally cylindrical plug shroud element is mounted coaxially on the plug unit and a generally cylindrical socket shroud element is mounted coaxially on the socket unit and conforms circumferentially with the plug shroud element. Finally, manually actuable means are mounted in one of the shroud elements and movable to engage the other of the shroud elements to prevent relative rotation as between the plug and socket units on their common axis. In this manner, the plug and socket units are safely locked and cannot be accidentally disengaged. In the preferred embodiment of the invention the plug shroud element extends to at least the end of the male electrical contacts and serves to protect these contacts against damage. In this embodiment, the manually actuable means comprises a key mounted in a keyway in one of the shroud elements, and a keyway is also provided in the other of the shroud elements. The key is slidable to engage both keyways simultaneously to effect the desired locking.