Sergei Yevgenyevich Aleinikov (Russian: Сергей Евгеньевич Алейников; Belarusian: Сярге́й Яўге́навіч Але́йнікаў, Syarhey Alyeynikaw; born 7 November 1961) is a Belarusian and Soviet former professional footballer, and currently a coach. He primarily played as a defensive midfielder and was known for his stamina, intelligence, solid technique, tactical sense, and passing ability. He also played in defence as a sweeper or centre-back.
Aleinikov was born in Minsk, Belarusian SSR. He played for the USSR national football team, making 73 appearances, scoring six goals, from 1984 to 1991, and was on the Soviet squad that made the final of Euro 1988, losing to the Netherlands 0–2. He also played for the CIS in 1992 and earned 4 caps for Belarus after the independence of Belarus, earning his final cap against Luxembourg in a Euro 1996 qualifier in 1994.
He joined Dinamo Minsk in 1981 and won the USSR championship the following season. The midfielder then joined Juventus F.C. in 1989, and won the UEFA Cup and Coppa Italia in 1990. He signed for U.S. Lecce in 1990, and in 1992 went to Japan to play for Gamba Osaka. He finished his career with Swedish side IK Oddevold in 1996.