The Informer is a 1935 American drama thriller film directed and produced by John Ford, adapted by Dudley Nichols from the 1925 novel of the same title by Irish novelist Liam O'Flaherty. Set in 1922, the plot concerns the underside of the Irish War of Independence and centers on a disgraced Republican man, played by Victor McLaglen, who anonymously informs on his former comrades and spirals into guilt as his treachery becomes known. Heather Angel, Preston Foster, Margot Grahame, Wallace Ford, Una O'Connor and J. M. Kerrigan co-star. The novel had previously been adapted for a British film of the same name in 1929.

Along with Mutiny on the Bounty, The Informer was a big contender at the 8th Academy Awards, competing directly in all six categories they were nominated for (though Mutiny got eight nominations in total, given its three Best Actor nominations). The Informer won four Oscars: Best Director for Ford, Best Actor for McLaglen, Best Writing Screenplay for Nichols, and Best Score for Max Steiner.

In 2018, the film was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant."