| John Cahan | |
| Birth Date: | 1 February 1889 |
| Birth Place: | Halifax, Nova Scotia, Canada |
| Death Place: | Halifax, Nova Scotia, Canada |
| Office: | MLA for Yarmouth County |
| Term Start: | 1925 |
| Term End: | 1928 |
| Predecessor: | Howard Corning |
| Successor: | Lindsay C. Gardner |
| Party: | Liberal-Conservative |
| Battles: | World War I |
| Allegiance: | Canadian Army |
| Unit: | 1st Canadian Division |
John Flint Cahan (February 1, 1889 – November 8, 1928) was a Canadian engineer and political figure in Nova Scotia, Canada. He represented Yarmouth County in the Nova Scotia House of Assembly from 1925 to 1928 as a Liberal-Conservative member.
He was born in Halifax, the son of Charles Cahan and Mary Chisholm. He was educated at Dalhousie University and McGill University.
Cahan served as a member of the Executive Council of Nova Scotia from 1925 to 1928. He also served as a captain in the 1st Canadian Pioneers during World War I; he was seriously wounded during the war and later died in Halifax at the age of 39 as the result of his wounds.
In 1912, Cahan married Beatrice Eleanor Davies.