Myrtis Loudermilk, a director at Johnson's Funeral Home in San Angelo, told The Associated Press that Kelton died Saturday of natural causes.
Kelton wrote 62 fiction and nonfiction books. "The Good Old Boys" was made into a 1995 TV movie starring Jones for the TNT cable network. Kelton also was known for "The Man Who Rode Midnight" and "The Time It Never Rained."
His first novel, "Hot Iron," was published in 1956, and he recently finished his last book, "Texas Standoff," due out next year. Another novel, "Other Men's Horses," will be released this fall.
The Western Writers of America voted Kelton "Best Western Author of All Time" and gave him its Spur Award seven times. Four of his books won the Western Heritage Award from the National Cowboy Hall of Fame.
Born in Crane, Kelton grew up on the McElroy Ranch in west Texas. He served in the U.S. Army from 1944 to 1946 and saw combat in Europe during World War II.
He earned a journalism degree from the University of Texas at Austin and spent 15 years as the farm and ranch writer-editor for the San Angelo Standard-Times. He also worked as an editor for Sheep and Goat Raiser Magazine and Livestock Weekly, from which he retired in 1990.
Funeral services are scheduled for 2 p.m. Thursday at First United Methodist Church in San Angelo.
Kelton is survived by his wife, Ann, and three children.