A sheet processing apparatus includes a controller configured to control operations of the pair of aligning members such that a sheet bundle disposed on a first stacking portion is aligned by the pair of aligning members of the pair of aligning members at a position shifted to a side of one aligning member in a width direction perpendicular to the discharge direction of a sheet with respect to a sheet discharge range in which a sheet is discharged at the time of discharging the sheet from a discharge portion, and, before the aligned sheet bundle is discharged to a second stacking portion by a bundle discharge portion, the other aligning member of the pair of aligning members is moved to the outside of the sheet discharge range in the width direction.