The basic physics and the various methods of optoelectronic microwave switching are reviewed. To achieve a clearly arranged presentation, the diverse techniques known to date are reported in the light of a trisection classification scheme according to three basic principles: the optical control of a photosensitive transmission path in CW-fed two-port devices, the optical control of charged-line pulsers or normally CW-operated solid-state oscillators, and the electrical control of photosensitivity in optically coupled microwave switching devices.