The invention concerns a rugged antenna mount adapter (100) for mounting an antenna (112) used by NATO vehicles to an existing antenna mount opening (113) of a non-NATO type armored vehicle, regardless of the thickness of the armor (110) on the vehicle. The antenna mount adapter has an upper member (116) and a lower member (118). The upper member (116) has two flanges (120, 122) separated by a hollow cylindrical body (116) having internal threads (134). The top flange (120) is adapted to receive a NATO style antenna and the bottom flange (122) is adapted to be attached to the outside surface and aligned with the antenna mount opening (113) of a non-NATO type armored vehicle. The lower member (118) is a hollow cylindrical body having a flange (140) at one end and a screw thread (136) which extends along the outside surface of the cylinder at the other end. The screw thread end of the lower member is designed to screw into the upper member from the interior of the vehicle until the flange on the lower member abuts the inside wall of the vehicle.