An electrical connector assembly has a first connector, to which a cable is connected, a second connector, which is mounted to a mounting face of a support member and into/from which the first connector is inserted/removed, and an intermediate member that prevents disengagement of the first connector from the second connector. The intermediate member has a mountable portion mounted directly, or mounted indirectly through an intermediary member, to the second connector, and a locking portion that prevents upward disengagement of the first connector, and, while the mountable portion is mounted to the second connector, the intermediate member is enabled for operational movement relative to the second connector between an open position that allows for the insertion/removal of the first connector into or from the second connector and a locked position in which disengagement of the first connector is prevented by the locking portion.