Juan Belaieff (Russian: ???? ?????????? ??????, Ivan Timofeyevich Belyaev, 19 April 1875, Saint Petersburg, Russia — 19 January 1957, Asunción, Paraguay) was a Russian and Paraguayan cartographer and soldier, notable for his investigation and mapping of the Gran Chaco region and for his role in the Paraguayan army during the Chaco War.