A calibration system for calibrating a radar sensing system for a vehicle includes at least one calibrating radar transmitter spaced from a location where the vehicle may be positioned. The vehicle includes a radar sensor disposed at the vehicle so as to sense exterior of the vehicle. The radar sensor includes a plurality of transmitters that transmit radio signals and a plurality of receivers that receive radio signals that are transmitted radio signals reflected from an object. A processor is operable to process an output of the receivers. With the vehicle positioned at the location, the at least one calibrating transmitter transmits signals that are received by the receivers of the radar sensor. Responsive to processing by the processor of the output of the receivers when receiving signals transmitted by the at least one calibrating transmitter, the calibration system determines if the radar sensor is misaligned at the vehicle.