| Birth Date: | 7 June 1940 |
| Birth Place: | Tula, Russian SFSR, Soviet Union |
| Death Date: | 10 November 1966 (aged 26) |
| Death Place: | Moscow, Russian SFSR, Soviet Union |
| Sport: | Boxing |
| Club: | Trudovye Rezervy |
| Show-Medals: | yes |
Sergey Aleksandrovich Sivko (Russian: Сергей Александрович Сивко, 7 June 1940 – 10 November 1966) was a Russian amateur boxer. In 1960 he won the Soviet flyweight title and an Olympic silver medal. Next year he moved to the bantamweight division and won the Soviet and European titles. He died aged 26 in 1966. Since 1975, an annual boxing tournament has been held in his honor in Moscow.