The present discloaure relates to a transmission apparatus, a transmission method, a reception apparatus, and a reception method which make it possible to control redundancy of a header in packet communication. A region representing a packet length in a header of a packet is set according to a size of a payload of an input packet. A header of a baseband packet includes a minimum fixed length header including type identification information for identification of a type of the input packet or the stream and information of a packet length of the input packet or the stream stored in a payload of the baseband flame packet.