| Honorific-Prefix: | The Honourable |
| Jack Slater | |
| Office: | Minister for Recreation and Sport Minister for Water Resources |
| Premier: | John Bannon |
| Predecessor: | Michael Wilson |
| Successor: | Kym Mayes |
| Term Start: | 10 November 1982 |
| Term End: | 18 December 1985 |
| Constituency Mp2: | Gilles |
| Parliament2: | South Australian |
| Predecessor2: | constituency established |
| Successor2: | Colin McKee |
| Term Start2: | 30 May 1970 |
| Term End2: | 24 November 1989 |
| Birth Name: | John William Slater |
| Birth Date: | 1927 9, df=yes |
| Birth Place: | Adelaide, Australia |
| Death Place: | Adelaide, Australia |
| Party: | Labor Party |
John William "Jack" Slater (3 September 1927 – 23 February 1997) was an Australian politician who represented the South Australian House of Assembly seat of Gilles for the Labor Party from 1970 to 1993. He was Minister of Recreation and Sport and Minister of Water Resources in the first term of the Bannon government from 1982 to 1985.[1]