John Clark Ketcham (January 1, 1873 – December 4, 1941) was a politician from the U.S. state of Michigan.

Ketcham was born in Toledo, Ohio, and moved with his parents to Maple Grove, Michigan near Nashville, the same year.

He was an unsuccessful candidate for reelection in 1932, losing in the general election to Democrat George E. Foulkes.

Ketcham was president of the National Bank of Hastings, 1933-1937; State commissioner of insurance, 1935-1937; and counsel for the Michigan Chain Store Bureau, 1938-1941.

He was the son-in-law, of Samuel Azariah Shelton, U.S. Representative from Missouri's 16th congressional district, 1921-1923.