Marcus Jonas Munuhe Olsson (born 17 May 1988) is a Swedish professional footballer who last played for Derby County as a midfielder and a left back.
Born in Gävle, Sweden, Olsson started his career at Högaborgs BK. In 2008, he signed a contract with Halmstad, replacing Martin Fribrock as left winger as Fribrock departed for Esbjerg fB in the summer of 2008. Mainly featured as left winger, he also used as a forward in several games, during Josep Clotet Ruiz time at Halmstad and the lack of a natural left side defender, Olsson and Kujtim Bala took turns on playing on the position. As Halmstads BK was relegated from Allsvenskan in 2011, Marcus announced that he would not sign a new contract with the club and that he would start searching for a new club to play for.
After rejecting a contract from Djurgårdens IF, and being linked to Standard Liège and Viking FK, Blackburn Rovers confirmed on 31 January that Olsson had signed a two-and-a-half-year contract with the club, joining his twin brother there.