Yuri Valentinovich Lonchakov (Russian: Юрий Валентинович Лончаков; born 4 March 1965) is a Russian cosmonaut and a veteran of two space missions.
Lonchakov was born in Balkhash and entered the Russian Air Force following graduation from high school in 1982. He served as a paratrooper and pilot and was selected as a cosmonaut candidate in 1997. Lonchakov's first spaceflight was Space Shuttle mission STS-100, visiting the International Space Station. Lonchakov again visited the ISS in 2002 aboard the Russian spacecraft Soyuz TMA-1.