The 1979–80 Sussex County Football League season was the 55th in the history of Sussex County Football League a football competition in England.[1] [2]
| Competition: | Sussex County Football League Division One |
| Season: | 1979–80 |
| Winners: | Chichester City |
| Relegated: | Haywards Heath Rye United |
| Matches: | 240 |
| Total Goals: | 734 |
| Prevseason: | 1978–79 |
| Nextseason: | 1980–81 |
Division One featured 14 clubs which competed in the division last season, along with two new clubs, promoted from Division Two:
Also, Steyning changed name to Steyning Town.
| Competition: | Sussex County Football League Division Two |
| Season: | 1979–80 |
| Winners: | Hastings Town |
| Promoted: | Hastings Town Three Bridges |
| Matches: | 182 |
| Total Goals: | 553 |
| Prevseason: | 1978–79 |
| Nextseason: | 1980–81 |
Division Two featured twelve clubs which competed in the division last season, along with two new clubs relegated from Division One: