Day of Anger (Italian: I giorni dell'ira, lit. "The Days of Wrath") is a 1967 Spaghetti Western film directed and co-written by Tonino Valerii and starring Lee Van Cleef and Giuliano Gemma, and features a musical score by Riz Ortolani. The film credits the novel Der Tod ritt dienstags ("Death Rode on Tuesdays") by Ron Barker (Rolf O. Becker) as its basis, although Valerii and screenwriter Ernesto Gastaldi have attested that this credit was primarily included to appease the West German co-producers, and that although some scenes are partially borrowed from it, the film is not an adaptation of Becker's novel.

Day of Anger was Valerii's second film, as well as his second Spaghetti Western, following Taste for Killing. Valerii went on to film his third Spaghetti Western, The Price of Power, also featuring Gemma, in 1969.