Siarhei Byk (Belarusian: ?????? ????????????? ???; born 8 July 1990) is a Belarusian foil fencer, member of the national team.
Byk earned a silver medal in the 2011 U23 European Championships in Kazan and a bronze medal in the 2013 edition of the same competition in Torun.
He reached the quarter-finals at the 2013 European Fencing Championships in Zagreb, but was defeated by James-Andrew Davis of Great Britain.