The invention discloses an image forming system and a recording material processing device. The image forming system includes an image forming unit; a stacking unit used for stacking the recording materials having the images formed thereon as a bundle and making a first edge part of each recording material align with a second edge part different from the first edge part; a first binding unit that binds, by a first binding operation, first edge portions of the bundle stacked on a stacking unit; a second binding unit that binds, by a second binding operation, second edge portions of the bundle; a reversing transporting unit that reverses front and back surfaces of the recording materials having the images formed thereon, and that transports the reversed recording materials to the stacking unit; and a controller that performs control to determine whether or not to cause the reversing transporting unit to reverse and transport the recording materials, on the basis of orientations of the images with respect to the recording materials and positions of the first and second binding operations.