The present invention is directed to the provision of a thermal transfer sheet that can realize a high maximum transfer density in printing, does not cause blocking during storage in a roll form, can suppress, in a roll form, the transfer of a dye onto a backside layer, which faces the dye layer, does not cause an abnormal transfer in which, in printing on an object, the dye is transferred together with a dye layer onto the object, can further reduce the density in a highlight part in printing, and can form printed matter which is excellent in reproduction of gradation from highlight to shadow without any trouble. The thermal transfer sheet comprises a base material, a heat resistant slip layer provided on one side of the base material, and a dye layer provided on the other side of the base material, wherein the dye layer comprises a binder resin having a loss modulus at 60° C. of not less than 107 Pa, a loss modulus at 100° C. of not less than 106 Pa and a loss modulus at 150° C. in the range of 104 Pa to 105 Pa.