There is provided a thermal transfer recording medium capable of obtaining high transfer sensitivity during high-speed printing, that is, decreasing the amount of a dye used in a dye layer; and preventing abnormal transfer during printing even after storage in a high-temperature and high-humidity environment. The thermal transfer recording medium (1) contains: a heat-resistant sliding layer (40) that is formed on one surface of a substrate (10); and an undercoat layer (20) and a dye layer (30) that are sequentially laminated on the other surface of the substrate (10), in which the undercoat layer (20) contains, as major components, a polyvinyl pyrrolidone and a polyvinyl alcohol having a crystallinity degree of 15% or higher, and the dye layer (30) contains an anthraquinone-based thermal transfer dye.