| Competition: | Irish League |
| Season: | 1965–66 |
| Winners: | Linfield 27th Irish title |
| Matches: | 132 |
| Total Goals: | 553 |
| League Topscorer: | Sammy Pavis (28) |
| Prevseason: | 1964–65 |
| Nextseason: | 1966–67 |
The 1965–66 Irish League was the 65th edition of the Irish League, the highest level of league competition in Northern Irish football. The league consisted of 12 teams, and Linfield won the championship.