1979–80 Sussex County Football League

The 1979–80 Sussex County Football League season was the 55th in the history of Sussex County Football League a football competition in England.

Division One
Division One featured 14 clubs which competed in the division last season, along with two new clubs, promoted from Division Two:
 * Pagham
 * Portfield

Also, Steyning changed name to Steyning Town.

Division Two
Division Two featured twelve clubs which competed in the division last season, along with two new clubs relegated from Division One:
 * East Grinstead
 * Sidley United