| James Caven Mahaffy | |
| Birth Date: | 29 August 1905 |
| Birth Place: | Port Elgin, Ontario[1] |
| Leader of the Official Opposition in Alberta | |
| Term Start: | February 18, 1943 |
| Term End: | March 30, 1943 |
| Predecessor: | Alfred Speakman |
| Successor: | James H. Walker |
| Term Start1: | 1940 |
| Term End1: | 1944 |
| Predecessor1: | Edith Gostick Ernest Manning John Irwin John Hugill |
| Successor1: | Rose Wilkinson Howard MacDonald Aylmer Liesemer |
| Office1: | MLA for Calgary |
| Party: | Independent Movement |
James Caven Mahaffy (August 29, 1905 – November 29, 1986) was a provincial level politician from Alberta, Canada. He served as a member of the Legislative Assembly of Alberta from 1940 to 1944. Mahaffy held a seat in the electoral district of Calgary as an Independent. Mahaffy briefly served as Leader of the Opposition.
Mahaffy ran for a seat in the 1940 Alberta general election. He was elected to the third seat in the Calgary electoral district as an Independent under the Alberta Unity Movement.[2]
He briefly served as Leader of the Opposition during the 3rd Session of the 9th Alberta Legislative Assembly.
Mahaffy did not run for a second term in 1944.