The Conqueror is a 1956 American epic historical drama film, directed by Dick Powell and written by Oscar Millard. It stars John Wayne as the Mongol conqueror Genghis Khan and co-stars Susan Hayward, Agnes Moorehead and Pedro Armendáriz. Produced by entrepreneur Howard Hughes, the film was principally shot near St. George, Utah.

Despite the stature of the cast and a respectable box office performance, the film was critically panned; it is often ranked as one of the worst films of the 1950s and also as one of the worst films ever made. Wayne, who was at the height of his career, had lobbied for the lead role after reading the script and was widely believed to have been grossly miscast. The Conqueror was listed in the 1978 book The Fifty Worst Films of All Time. In 1980, Wayne posthumously received a Golden Turkey Award (awarded to movies and performances considered the worst in history) in the "Worst Casting" category, for his performance as Khan. In the years since release, the film garnered additional controversy for its filming downwind of a nuclear testing site, which sparked debate among historians and biologists over whether or not it caused multiple cases of cancer among the cast and crew.