Marcus Rediker (Owensboro, Kentucky, October 14, 1951) is an American professor, historian, essayist, and activist. He is a specialist in maritime social history and piracy.

Marcus Rediker graduated from Virginia Commonwealth University in 1976. He later studied at the University of Pennsylvania where he obtained a doctorate in history. He teaches courses at Georgetown University between 1982 and 1994. He lives for a year in Moscow (1984-5).

Marcus Rediker is currently Professor of Atlantic History and Professor of the Department of History at the University of Pittsburgh. Rediker has written several books on the social aspects of maritime history. He considers the 18th century sailors and pirates to be the forerunners of modern anti-capitalist movements.

In 2002, Rediker published in collaboration with Peter Linebaugh The Hydra of Revolution: Sailors, Slaves, and Peasants in the Hidden History of the Atlantic. The American historian Howard Zinn has described it as "a wonderful book in which Linebaugh and Rediker recover the lost history of resistance to capitalist conquest on both sides of the Atlantic."