A photocontrolled InGaAs/AlAs double‐barrier resonant‐tunneling diode, for the first time, has been demonstrated. The photoinduced valley current in the resonant‐tunneling diode was optically controlled by varying the incident optical power level. With the incident optical power intense enough, the photogenerated valley current became dominant over the peak current. As a consequence, the negative differential resistance of the device was nullified. A photogeneration process, based on photogenerating carriers in the depletion region adjacent to the double barriers, is described and characterized. The device under illumination was modeled as a resonant‐tunneling diode in series integration with a photodetector. The quantum efficiency for the photogeneration was measured and found comparable with theoretical prediction. The demonstrated photocontrolled double‐barrier resonant‐tunneling diode can be useful in a variety of applications.