A sheet processing system according to an embodiment includes a tray that supports a sheet on opposite sides of the sheet orthogonal to a conveyance direction of the sheet. The tray includes a first adjustable support and second adjustable support positioned opposite the first adjustable support in the direction orthogonal to the conveyance direction of the sheet. A skew sensor detects a skew angle of the sheet conveyed to the tray. A corner sensor detects positions of each corner on a front end in the downstream direction of the sheet conveyed to the tray. A controller controls movement of the first and second adjustable supports based on the detected skew angle and the detected positions of each corner on the front end of the sheet conveyed to the tray so that the sheet is conveyed to the tray without jamming.