A sheet processing apparatus includes a conveyance roller pair that rotates in a certain direction to convey a sheet, a first normal-reverse rotation roller pair that is capable of rotating in a normal direction and a reverse direction and rotates to convey the sheet, a first driver that drives the first normal-reverse rotation roller pair to rotate, and a first driving force transmitter that transmits a driving force of the first driver for rotating the first normal-reverse rotation roller pair in a first specific direction to the conveyance roller pair so as to rotate the conveyance roller pair in the certain direction, and blocks a driving force of the first driver for rotating the first normal-reverse rotation roller pair in the direction opposite to the first specific direction from being transmitted to the conveyance roller pair.