1977–78 Sussex County Football League

The 1977–78 Sussex County Football League season was the 53rd 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:
 * Arundel
 * Shoreham

Division Two
Division Two featured twelve clubs which competed in the division last season, along with three new clubs:
 * Albion United, joined from the East Sussex League
 * Three Bridges, relegated from Division One
 * Whitehawk, relegated from Division One