Rio Lobo is a 1970 Western movie starring John Wayne. The film was the last film directed by Howard Hawks, from a script by Leigh Brackett. The film was shot in Technicolor with a running time of 114 minutes. The musical score was composed by Jerry Goldsmith and the movie was filmed at Cuernavaca in the Mexican state of Morelos and at Tucson, Arizona.

It was the third film in a trilogy directed by Hawks varying the idea of a sheriff defending his office against belligerent outlaw elements in the town: the other two films were Rio Bravo (1959) and El Dorado (1966), both also starring John Wayne.

The film opens during the American Civil War. Col. Cord McNally (John Wayne) has instructions telegraphed to his close friend, Lt. Forsythe (Peter Jason), in charge of the Union troops on a Union army payroll train. However, Confederates led by Capt. Pierre Cordona (Jorge Rivero) and Sgt. Tuscarora Phillips (Christopher Mitchum) hijack the train. They have an elegant plan of listening in on the telegraph wires, greasing the tracks to stop the train, disconnecting the payroll wagon from the engine so it would roll back down the hill, using a hornet's nest to force the Union guards to jump off the train, then catching the train with many ropes tied to trees. In the process, Lt. Forsythe is fatally injured.