Thomas Alexandrovich de Hartmann (Russian: Фома́ Александро́вич Га́ртман) September 21, 1885 – March 28, 1956 was a Russian composer and prominent student and collaborator of George Gurdjieff. Thomas de Hartmann was born in Khoruzhivka, Poltava Governorate, Russian Empire, now Sumy Oblast, Ukraine. At the age of 18 he received his diploma from the Saint Petersburg Conservatory. He studied conducting in Munich with Felix Mottl before World War I.