| Honorific-Prefix: | The Hon. |
| William Frederic Kay | |
| Constituency Mp: | Missisquoi |
| Parliament: | Canadian |
| Predecessor: | Daniel Bishop Meigs |
| Successor: | District was abolished in 1924 |
| Term Start: | 1911 |
| Term End: | 1930 |
| Birth Date: | 18 May 1876 |
| Birth Place: | Montreal, Quebec, Canada |
| Party: | Liberal |
| Cabinet: | Minister Without Portfolio (1930) |
William Frederic Kay, (May 18, 1876 - May 8, 1942) was a Canadian politician.
Born in Montreal, Quebec, he was first elected to the House of Commons of Canada representing the Quebec riding of Missisquoi in the 1911 federal election. A Liberal, he was re-elected in 1917, 1921, 1925, and 1926. In June 1930, he was appointed a Minister without Portfolio in the cabinet of MacKenzie King. He was defeated in the July 1930 federal election.