| Ulster Cup | |
| Year: | 1965–66 |
| Num Teams: | 12 |
| Defending Champions: | Linfield |
| Winners: | Coleraine (1st win) |
| Second: | Linfield |
| Matches: | 66 |
| Goals: | 261 |
| Prev Season: | 1964–65 |
| Next Season: | 1966–67 |
The 1965–66 Ulster Cup was the 18th edition of the Ulster Cup, a cup competition in Northern Irish football.[1]
Coleraine won the tournament for the 1st time, finishing top of the group standings.[2]