John Cunningham Kelton (June 24, 1828 – July 15, 1893) was an American military officer who was Adjutant General of the United States Army from 1889 to 1892.

Kelton was born in Delaware County, Pennsylvania and graduated from the United States Military Academy in 1851.

When the American Civil War began, Kelton was made Chief Purchasing Commissary at St. Louis for supplying troops in the West.

He resigned his volunteer commission on March 12, 1862, and in turn served as Assistant Adjutant General of the Department of Mississippi in 1862.

He was appointed as adjutant general of the Division of the Pacific in July 1870, where he remained until September 1885, earning a promotion to colonel in June 1880.