[Problem] To provide: a decoding device that decodes and replays, in a suitable order, sequentially transmitted information; a reception device; a transmission/reception system; a decoding method; and a storage medium having the decoding program stored therein. [Solution] A decoding unit 21 that decodes packets sent from a transmission device 10. A decoding order determination unit 22 determines the order of packets to be decoded by the decoding unit 21, on the basis of adjustment information that is included in the packet and corresponds to a time adjustment for making Coordinated Universal Time approach Universal Time. The packets include order information indicating the order in the same IP data flow. The decoding order determination unit 22 determines, on the basis of the order information, the order of packets to be decoded by the decoding unit 21, if the adjustment information indicates that a time adjustment will occur.