Justin R. Whiting (February 18, 1847-January 31, 1903) was a politician from the U.S. state of Michigan.
Whiting was born in Bath, New York, and moved to Michigan in 1849 with his parents, who settled in St. Clair, Michigan. He attended the public schools and the University of Michigan at Ann Arbor from 1863 to 1865. He worked as a merchant and manufacturer. Whiting was elected mayor of St. Clair in 1879 and represented the 17th District in the Michigan State Senate in 1882. He was elected as a Democrat to the Fiftieth Congress and reelected to the Fifty-first, Fifty-second, and Fifty-third Congresses, serving from March 4, 1887 until March 3, 1895]]. After leaving Congress, Whiting resumed his former business pursuits in St. Clair. He was an unsuccessful Fusion candidate for Governor of Michigan in 1898, losing to incumbent Republican Hazen S. Pingree. He also ran for election in 1900 to the Fifty-seventh Congress, losing to incumbent Republican Edgar Weeks.
Whiting married Emily Owen, and his son, also named Justin Rice Whiting (1886-1965), was president of the Consumers Power Company from 1949 to 1959.
Whiting also served as chairman of the Democratic State central committee. He died in St. Clair and is interred there at Hillside Cemetery.