A new type of GaAs electro-optic directional-coupler switch for monolithic integrated optics has been proposed and demonstrated. The devices were fabricated from a pair of closely spaced low-loss (α ≈ 2.2 dB/cm at 1.15 μm) single-mode rib waveguides with Au Schottky barriers. A 30 dB extinction ratio in the input channel was measured at a reverse-bias voltage of 24 V and the switches have a potential bandwidth of 2 GHz.