Georgi Mikhailovich Grechko (Russian: Георгий Михайлович Гречко; born May 25, 1931 in Leningrad) was a Soviet cosmonaut who flew on three space flights: Soyuz 17, Soyuz 26, and Soyuz T-14.

Grechko graduated from the Leningrad Institute of Mechanics with a doctorate in mathematics. He went on to work at Sergei Korolev's design bureau and from there was selected for cosmonaut training for the Soviet moon programme. When this did not eventuate, he went on to work on the Salyut space stations.

He resigned from the space programme in 1992 to lecture in atmospheric physics at the Soviet Academy of Sciences.