The 1965–66 Sussex County Football League season was the 41st in the history of Sussex County Football League a football competition in England.[1] [2]
| Competition: | Sussex County Football League Division One |
| Season: | 1965–66 |
| Winners: | Bexhill Town Athletic |
| Relegated: | Arundel Wigmore Athletic |
| Matches: | 240 |
| Total Goals: | 1044 |
| Prevseason: | 1964–65 |
| Nextseason: | 1966–67 |
Division One featured 14 clubs which competed in the division last season, along with two new clubs, promoted from Division Two:
| Competition: | Sussex County Football League Division Two |
| Season: | 1965–66 |
| Winners: | Horsham YMCA |
| Promoted: | Horsham YMCA Newhaven |
| Matches: | 306 |
| Total Goals: | 1645 |
| Prevseason: | 1964–65 |
| Nextseason: | 1966–67 |
Division Two featured 16 clubs which competed in the division last season, along with two new clubs, relegated from Division One: