An object of the invention is to provide a photo-alignment copolymer capable of improving upper layer coatability after layer formation, a binder composition, a binder layer, an optical laminate, and an image display device. A photo-alignment copolymer according to the embodiment of the invention has a repeating unit A including a photo-alignment group, a repeating unit B including a crosslinkable group which causes a crosslinking reaction by the action of at least one selected from the group consisting of light, heat, an acid, and a base, and a repeating unit C including a cleaving group which decomposes by the action of at least one selected from the group consisting of light, heat, an acid, and a base to produce a polar group, and the repeating unit C has the cleaving group on a side chain, and has a group of atoms which is provided on a side closer to a terminal than the cleaving group on the side chain to be able to unevenly distribute the photo-alignment copolymer on an air interface side.