| Ian Grant Wahn | |
| Parliament: | Canadian |
| Riding: | St. Paul's |
| Term Start: | June 18, 1962 |
| Term End: | October 29, 1972 |
| Predecessor: | Roland Michener |
| Successor: | Ron Atkey |
| Birth Date: | 18 April 1916 |
| Birth Place: | Herbert, Saskatchewan, Canada |
| Profession: | Lawyer |
| Party: | Liberal |
Ian Grant Wahn (April 18, 1916 – October 14, 1999) was a Canadian politician and lawyer. He was elected to the House of Commons of Canada as a Member of the Liberal Party in the riding of St. Paul's in the 1962 election. He was re-elected in 1963, 1965, 1968 and defeated in 1972. Prior to his federal political career, he was a captain in the Canadian Army (Supplementary Reserve).