Sergei Ivanovich Ovchinnikov (Russian: Серге́й Ива́нович Овчи́нников, IPA: [sʲɪrˈɡʲej ɪˈvanəvʲɪtɕ ɐfˈtɕinʲːɪkəf]; born 10 November 1970 in Moscow) or Boss is a manager and former association football goalkeeper who played for the Russian national team.

In 1992, he asserted himself in Yuri Syomin's first choice squad and remained the main goalkeeper until his move to Benfica in 1997.

In 2006 Dynamo released Ovchinnikov, after the goalkeeper got involved in a clash with a referee Igor Zakharov.

In April 2007 Sergei Ovchinnikov became Lokomotiv Moscow club goalkeeping coach and started to work with children and the reserves.

Next, he became the new manager of Kuban Krasnodar in the 2009 Russian Premier League season but was sacked on 9 August, after a 0–2 defeat at home, against Saturn.