War Is a Racket is a speech and a 1935 short book by Smedley D. Butler, a retired United States Marine Corps Major General and two-time Medal of Honor recipient. Based on his career military experience, Butler discusses how business interests commercially benefit from warfare. He had been appointed commanding officer of the Gendarmerie during the 1915–1934 United States occupation of Haiti.

After Butler retired from the US Marine Corps in October 1931, he made a nationwide tour in the early 1930s giving his speech "War Is a Racket". The speech was so well received that he wrote a longer version as a short book published in 1935. His work was condensed in Reader's Digest as a book supplement, which helped popularize his message. In an introduction to the Reader's Digest version, Lowell Thomas praised Butler's "moral as well as physical courage". Thomas had written Smedley Butler's oral autobiography.

According to the HathiTrust online library, the book published in 1935 is in the public domain. A scanned copy of the original 1935 printing is available for download, in part or in whole, on the HathiTrust website, along with a detailed description of the copyrights.