Serhiy Saveliyovych Onopko (Ukrainian: Сергій Савелійович Онопко; born 26 October 1973) is a Ukrainian retired professional footballer who played as a midfielder.

During his career Onopko played for Shakhtar Donetsk, Mykolaiv, Vorskla Poltava, Inter Baku, Dnipro Cherkasy and Hirnyk Kryvyi Rih.

He is a younger brother of Viktor Onopko.

Shakhtar Donetsk

• Ukrainian Premier League runner-up: 1993–94, 1996–97, 1997–98
• Ukrainian Cup: 1994–95, 1996–97

• Serhiy Onopko at WorldFootball.net
• Serhiy Onopko: Nobody was inviting my brother to the Ukrainian national team, yet to the Russian they called right away. UA-Football. 27 December 2007
• Serhiy Onopko at UAF and archived FFU page (in Ukrainian)
• Serhiy Onopko at FootballFacts.ru (in Russian)