The Academy of St Martin in the Fields is an English chamber orchestra, based in London.

John Churchill and Sir Neville Marriner founded the orchestra as The Academy of St.-Martin-in-the-Fields in London as a small, conductorless string group. The original group numbered 11, all male. Their name comes from Trafalgar Square's St Martin-in-the-Fields church, where the orchestra gave its first concert on November 13, 1959. In 1988, the orchestra dropped the hyphens from its full name. Marriner holds the title of Life President.