The Vostok programme (Orient or East) was a Soviet human spaceflight project to put the first Soviet citizens into low Earth orbit and return them safely.

Competing with the United States Project Mercury, it succeeded in placing the first human into space, Yuri Gagarin.

The Vostok capsule was developed from the Zenit spy satellite project, and its launch vehicle was adapted from the existing R-7 Semyorka intercontinental ballistic missile (ICBM) design. The name "Vostok" was treated as classified information until Gagarin's flight was first publicly disclosed to the world press.

The programme carried out six crewed spaceflights between 1961 and 1963. The longest flight lasted nearly five days, and the last four were launched in pairs, one day apart. This exceeded Project Mercury's demonstrated capabilities of a longest flight of just over 34 hours, and of single missions.

Vostok was succeeded by two Voskhod programme flights in 1964 and 1965, which used three- and two-man modifications of the Vostok capsule and a larger launch rocket.