| John M. Clancy | |
| Birth Date: | 7 May 1837 |
| Birth Place: | County Laois, Ireland |
| Death Place: | Butte, Montana |
| Occupation: | real estate |
| Office: | Member of the U.S. House of Representatives from New York |
| Constituency: | (1889–93) (1893–95) |
| Term Start: | March 4, 1889 |
| Term End: | March 3, 1895 |
| Predecessor: | Peter P. Mahoney |
| Successor: | Denis M. Hurley |
| Office1: | Member of the New York State Assembly |
| Constituency1: | 1st Kings (1878–79) 4th Kings (1880–81) |
| Term Start1: | 1878 |
| Term End1: | 1881 |
John Michael Clancy (May 7, 1837 – July 25, 1903) was an American businessman and politician who served three terms as a United States representative from New York from 1889 to 1895.
Born in County Laois, Ireland, he immigrated with his parents to the United States and settled in New York City. He attended the public schools of Brooklyn, engaged in the real-estate business, served as an alderman of the city of Brooklyn from 1868 to 1875, and was a member of the New York State Assembly in 1878, 1879 (both Kings Co., 1st D.), 1880 and 1881 (both Kings Co., 4th D.).
Clancy was elected as a Democrat to the Fifty-first, Fifty-second, and Fifty-third Congresses (March 4, 1889 – March 3, 1895); he was not a candidate for renomination in 1894.
He then resumed the real-estate business in New York City. He was an unsuccessful candidate for election in 1896 to the Fifty-fifth Congress and died in Butte, Montana while returning from a visit to Yellowstone Park. Interment was in Holy Cross Cemetery, New York City.