Gary Mark Gilmore (December 4, 1940 – January 17, 1977) was an American criminal who gained international attention for demanding the implementation of his death sentence for two murders he committed in Utah. After the U.S. Supreme Court upheld a new series of death penalty statutes in the 1976 decision Gregg v. Georgia, he became the first person in almost ten years to be executed in the United States. These new statutes avoided the problems under the 1972 decision in Furman v. Georgia, which had resulted in earlier death penalty statutes being deemed as "cruel and unusual" punishment, and therefore unconstitutional. (The Supreme Court had previously ordered all states to commute death sentences to life imprisonment after Furman v. Georgia.) Gilmore was executed by firing squad in 1977. His life and execution were the subjects of the 1979 nonfiction novel The Executioner's Song by Norman Mailer, and 1982 TV film of the novel starring Tommy Lee Jones as Gilmore.

In 1962, Gilmore was arrested again and sent to the Oregon State Penitentiary for armed robbery and assault. He faced assault and armed robbery charges again in 1964 and was given a 15-year prison sentence as a habitual offender. A prison psychiatrist diagnosed him with antisocial personality disorder with intermittent psychotic decompensation. He was granted a conditional release in 1972 to live weekdays in a halfway house in Eugene, Oregon, and study art at a community college. Gilmore never registered and, within a month, he was arrested and convicted of armed robbery.

Due to his violent behavior in prison, Gilmore was transferred in 1975 from Oregon to the federal prison in Marion, Illinois, at the time a maximum security facility.

Gilmore was conditionally paroled in April 1976 and went to Provo, Utah, to live with a distant cousin, Brenda Nicol, who tried to help him find work. Gilmore worked briefly at his uncle Vern Damico's shoe repair shop and then for an insulation company, but he soon returned to his previous lifestyle of stealing, drinking, and getting into fights. Gilmore, then 35, had a relationship with Nicole Baker, a 19-year-old widow, and divorcee who had two young children. The relationship was at first casual, but soon became intense and strained due to Gilmore's aggressive behavior and pressure from Baker's family to stop her seeing him.

On the evening of July 19, 1976, Gilmore robbed and murdered Max Jensen, a gas station employee in Orem, Utah. The next evening, he robbed and murdered Bennie Bushnell, a motel manager in Provo. Although both men had complied with his demands, he murdered each of them. While disposing of the .22 caliber pistol used in both killings, Gilmore accidentally shot himself in his right hand, leaving a trail of blood to the service garage, where he had left his truck to be repaired prior to murdering Bushnell.