The Plow That Broke the Plains (1936) is a short documentary film which shows what happened to the Great Plains region of the United States and Canada when uncontrolled agricultural farming led to the Dust Bowl. It was written and directed by Pare Lorentz.

Lorentz worked on the film with composer Virgil Thomson, who shared Lorentz’s enthusiasm for folk music and incorporated many folk melodies, along with other popular and religious music, into the soundtrack. The film was narrated by the American baritone Thomas Hardie Chalmers.

The film was sponsored by the United States government (Resettlement Administration) to raise awareness about the New Deal and was intended to cost $6,000 or less; it eventually cost over $19,000 and Lorentz, turning in many receipts written on various scraps of paper, had many of his reimbursements denied and paid for much of the film himself. Lorentz later faced criticism for appearing to blame westward bound settlers for the ecological crisis by having eroded the soil of the Plains with unrestrained farming (and one of his photographers, Arthur Rothstein, was criticized for moving a skull from one location to another in the Dust Bowl to shoot it and for other stagings in the film), but the film nonetheless succeeded in driving home the message of the severity of the problem caused by the misuse of land.

Virgil Thomson compiled a concert suite from his original score, which has been performed and recorded. One of the earliest recordings was for Vanguard Records with Leopold Stokowski conducting the Symphony of the Air; the original stereo LP also included a suite from Thomson’s score for another Lorentz documentary, The River.

In 1999, The Plow That Broke the Plains was selected for preservation in the United States National Film Registry by the Library of Congress as being “culturally, historically, or aesthetically significant”.