Otto John Maenchen-Helfen (German: Otto Mänchen-Helfen; July 26, 1894 – January 29, 1969) was an Austrian academic, sinologist, historian, author, and traveler.

When the Nazi Party came to power in Germany, he returned to Austria, and after the Anschluss in 1938 he emigrated to the United States, eventually becoming a professor at the University of California, Berkeley.

He was the author of several oft-cited books, including a history of the Huns.

He was the first non-Russian to travel and report on Tannu Tuva.

He obtained permission to travel there and study its inhabitants in 1929.