One Bull, sometimes given as Lone Bull, later known as Henry Oscar One Bull, was a Lakota Sioux man best known for being the nephew and adopted son of Sitting Bull. He fought at Battle of the Little Bighorn and, in his later years, provided interviews about his life as a warrior.

Sitting Bull was a Hunkpapa Lakota leader who led his people during years of resistance against United States government policies. Sitting Bull was killed by Indian agency police on the Standing Rock Indian Reservation during an attempt to arrest him at a time when authorities feared that he would join the Ghost Dance movement.