An image forming apparatus, including a main chassis having a discharge tray and a switchback tray in an upper position with respect to the discharge tray; an image forming unit; a discharge roller to discharge a recording sheet conveyed through the image forming unit onto the discharge tray; a duplex conveyer to invert the sheet and convey the inverted sheet to return to the image forming unit; and a switchback roller being rotatable in a normal direction to convey the sheet toward the switchback tray and a reverse direction to convey the sheet to the duplex conveyer; is provided. The main chassis includes a pair of walls, each of which extends in a vertical direction and in a conveying direction of the sheet and is arranged in adjacent to the switchback tray such that the switchback tray is interposed between the pair of walls.