The purpose of the present invention is to provide a thermal transfer sheet which can prevent a kick and a scumming, and can form a photographic tone color image of high quality with a continuous tone image by sublimation transfer, while expanding the range of choices for colorants to be included in a colorant layer; a coating liquid for colorant layer to be used for forming the colorant layer of this thermal transfer sheet; a method for manufacturing this thermal transfer sheet; and image forming method employing this thermal transfer sheet. The problem is solved by a thermal transfer sheet (1) in which at least a colorant layer (3) is layered on a substrate sheet (2), wherein the colorant layer (3) contains a predetermined solvent, a colorant (10x) dispersible in the predetermined solvent, a dispersant, and a binder resin, and the dispersant being one or more selected from the group consisting of polyether-based dispersants, graft type polymer dispersants, acryl-based block type polymer dispersants, urethane-based polymer dispersants and azo-based dispersants.