A switchable 0°/180° phase shifter on a balanced transmission line is provided. In one embodiment, the invention relates to an apparatus for providing 0°/180° phase shifting for a transmit/receive antenna pair including a transmit element and a receive element coupled by a balanced transmission line having two sections, the apparatus including a first section of the balanced transmission line, the first section including a first conductor and a second conductor, a second section of the balanced transmission line, the second section including a third conductor and a fourth conductor, and a switch disposed between the first section and the second section, wherein in a first configuration, the switch couples the first conductor to the third conductor and the second conductor to the fourth conductor, and in a second configuration, the switch couples the first conductor to the fourth conductor and the second conductor to the third conductor.