Heinrich Franz Friedrich Tietze (August 31, 1880 – February 17, 1964) was an Austrian mathematician, famous for the Tietze extension theorem on functions from topological spaces to the real numbers.

Tietze's graph is also named after him; it describes the boundaries of a subdivision of the Möbius strip into six mutually-adjacent regions, found by Tietze as part of an extension of the four color theorem to non-orientable surfaces.

He was born in Schleinz, Austria-Hungary, and studied mathematics at the Technische Hochschule in Vienna beginning in 1898.

After additional studies in Munich, he returned to Vienna, completing his doctorate in 1904 and his habilitation in 1908.

[1] From 1910 until 1918 Tietze taught mathematics in Brno, and was promoted to ordinary professor in 1913.