The present technology relates to a data processing apparatus and a data processing method capable of achieving higher convenience in a case where a plurality of transmission formats is available in a transmission frame. The data processing apparatus installed in a transmission-side facility processes a transmission frame transmitted as a broadcast signal and adds identification information for identifying the transmission format of the transmission frame, while a data processing apparatus installed in a reception-side facility processes a transmission frame in which a transmission frame has been identified, on the basis of identification information added to the transmission frame transmitted as the broadcast signal. The present technology can be applied as a method of a test stream, for example.