The present technology relates to a transmission device, a transmission method, a reception device, and a reception method that can improve transmission efficiency. An encoded signal is generated based on realtime data indicated by a waveform L using a predetermined fixed bit rate as a maximum code amount Sx and the encoded signal into which non-realtime data with an insufficient code amount is inserted is transmitted at the fixed bit rate, as indicated by a range Z12, when a code amount of the generated encoded signal is insufficient for the maximum code amount Sx. The present technology can be applied to broadcasting communication.