Gratton Hanley "Grat" Dalton (March 30, 1861 – October 5, 1892) was an American outlaw in the American Old West. He was one of three brothers in the Dalton Gang, led by his younger brother Bob Dalton. Both brothers were killed during a shootout in an ill-fated raid on two banks in Coffeyville, Kansas. Their brother Emmett Dalton survived to be convicted and imprisoned for fourteen years.