To provide a thermal transfer sheet capable of inhibiting residues derived from a back face layer from adhering to a thermal head, also capable of inhibiting occurrence of a kick, and having a shorter time period until the back face layer is stabilized.
A thermal transfer sheet comprising; a colorant layer located on one surface of a substrate and a back face layer located on the other surface of the substrate, wherein the back face layer comprises a binder resin and inorganic particles, and the binder resin comprises a product obtained by reacting a polyisocyanate having an isocyanurate structure with a resin having hydroxyl groups at an equivalent ratio of isocyanate groups in the polyisocyanate having an isocyanurate structure to hydroxyl groups in the resin having hydroxyl groups (—NCO/—OH) of 0.05 or more and 0.15 or less.