Sergei Martynov or Sergey Martynov may refer to:
Sergey Martynov (archer) (born 1965), Kazakh archer Sergei Martynov (politician) (born 1953), former Belarusian Minister for Foreign Affairs Sergey Martynov (politician) (born 1959), Russian senator Sergei Martynov (serial killer) (born 1962), Russian serial killer accused of killing nine women between 1992 and 2010 Sergei Martynov (sport shooter) (born 1968), Belarusian rifle shooter Sergey Martynov (wrestler) (1971–1997), Russian Greco-Roman wrestler