An occupancy sensor with a separable override unit can selectively override the operation of the occupancy sensor at designated times and for selected time intervals. The occupancy sensor includes a light sensor to actuate the occupancy sensor and a light assembly when the ambient light is below a predetermined level and to deactivate the occupancy sensor when the ambient light is above a threshold level. The override unit is provided with a light source, such as an LED, to emit light to actuate the light sensor of the occupancy sensor, thereby controlling the occupancy sensor, such as by preventing the occupancy sensor from being actuated. The occupancy sensor includes a cavity for receiving the override unit with the LED aligned with the light sensor: A control unit is operatively connected to one or more override units for selectively controlling the normal operation of the occupancy sensor.