Seamus McGarvey, ASC, BSC (born 29 June 1967) is a cinematographer from Armagh, Northern Ireland. He lives in Tuscany, Italy.

He has received two Academy Award nominations for his cinematography, on Joe Wright's 2007 drama Atonement and his 2012 adaptation of Leo Tolstoy's novel Anna Karenina.

In addition to the Oscar nominations, McGarvey won the British Society of Cinematographers (B.S.C.) award for Anna Karenina and for Nocturnal Animals, as well as a nomination for Atonement, and earned BAFTA nominations for Atonement, Anna Karenina, and Nocturnal Animals. He received A.S.C. nods for Atonement and Anna Karenina. Atonement earned him nominations for the British Independent Film Award, the Chicago Film Critics Association, and the Online Film Critics Society, and he received the top honour from the Phoenix Film Critics Society.

McGarvey has won three Evening Standard British Film Awards for Atonement, Anna Karenina, and Stephen Daldry's The Hours, and six Irish Film & Television Awards for Atonement, Anna Karenina, Sahara, We Need to Talk About Kevin, Nocturnal Animals, and The Greatest Showman. In 2004, he was awarded the Royal Photographic Society's prestigious Lumiere Medal, along with Jack Cardiff, Freddie Francis, Roger Deakins, and Ridley Scott, for contributions to the art of cinematography.