A sheet processing apparatus includes a buffering portion having a reverse conveyance roller pair and an intermediate roller pair, with the reverse conveyance roller pair reversing a conveyance direction of a sheet received from a first conveyance path and delivering the reversed sheet into a second conveyance path and being configured to come into contact with and be separated from each other. The intermediate roller pair is disposed in the second conveyance path and disposed upstream of a conveyance roller pair in a sheet conveyance direction, and the reverse conveyance roller pair is caused to nip a first sheet and a second sheet by causing the reverse conveyance roller pair to abut each other after receiving the second sheet by the reverse conveyance roller pair from the first conveyance path in a state in which the intermediate roller pair nips the first sheet reversed by the reverse conveyance roller pair and the reverse conveyance roller pair is separated from each other.