| Thomas Kerr Slack | |
| Office1: | Ontario MPP |
| Term Start1: | 1926 |
| Term End1: | 1934 |
| Predecessor1: | Charles Robert McKeown |
| Successor1: | Riding abolished |
| Term Start2: | 1919 |
| Term End2: | 1923 |
| Predecessor2: | Charles Robert McKeown |
| Successor2: | Charles Robert McKeown |
| Constituency2: | Dufferin |
| Party: | United Farmers, 1919-1923 Progressive, 1926-1934 |
| Birth Date: | 19 February 1875 |
| Birth Place: | Dufferin County, Ontario |
| Death Place: | Shelburne, Ontario |
| Occupation: | Farmer |
Thomas Kerr Slack (February 19, 1875 – November 1, 1956) was an Ontario farmer and political figure. He represented Dufferin in the Legislative Assembly of Ontario from 1919 to 1923 as a United Farmers member and from 1926 to 1934 as a Progressive member.
He was born in Melancthon Township, Dufferin County, Ontario, the son of Richard Slack, an immigrant from Ireland, and Elizabeth Silk. In 1905, he married Margaret Brown. Slack served as clerk for Melancthon township. He later moved to Orangeville.[1] He died suddenly at the Shelburne District Hospital in 1956 and was buried in Shelburne Cemetery.[2] [3]