According to Wikepedia, Vostok 1 was the first spaceflight in the Vostok program and the first human spaceflight in history. The Vostok 3KA spacecraft was launched on April 12, 1961. The flight took Yuri Gagarin, a cosmonaut from the Soviet Union, into space. The flight marked the first time that a human entered outer space, as well as the first orbital flight of a manned vehicle. Vostok 1 was launched by the Soviet space program, and was designed by Soviet engineers guided by Sergei Korolev under the supervision of Kerim Kerimov and others.
Source SPACE.com: All about our solar system, outer space and exploration