The present disclosure relates to a data processing device, a receiving device, a data processing method, and a program capable of suppressing degradation in quality in a case of reproducing data. In one example, a packet selection units selects one service stream from a multiplexed stream obtained by multiplexing a plurality of service streams. An insertion unit inserts null packets with time information, in which predetermined time information has been given to payloads, to spaces that become empty when the packet selection unit generates the one service stream. Thereafter, in the streams which have been demultiplexed after being multiplexed, the timing to output the null packets is adjusted with reference to the time information inserted in-to the null packets.