Marcin Grzegorz Dorociński (Polish: [ˈmart͡ɕin dɔrɔˈt͡ɕiɲskʲi]; born 22 June 1973) is a Polish film, television and stage actor. He is known for playing roles in such films as Pitbull(2005), Reverse (2009), Rose (2011), Jack Strong (2014), Hurricane (2018) and Mission: Impossible – Dead Reckoning Part One (2023), as well as internationally produced TV series Spies of Warsaw (2013) and The Queen's Gambit (2020).

Dorociński was born in Milanówek and grew up in a small village, Kłudzienko. His father is a blacksmith, and his mother is a housewife. He has three brothers, all of whom are police officers. He dreamt of becoming a professional football player. However, he was forced to give up the plan after sustaining a significant leg injury. He attended the vocational school in Grodzisk Mazowiecki and obtained a machinist certificate. The first person to notice his talent for acting was his history teacher, who encouraged him to become an actor. In 1993, he enrolled at the Aleksander Zelwerowicz State Theatre Academy.