1965–66 Sussex County Football League

The 1965–66 Sussex County Football League season was the 41st 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:
 * Sidley United
 * Southwick

Division Two
Division Two featured 16 clubs which competed in the division last season, along with two new clubs, relegated from Division One:
 * Hastings Rangers
 * Newhaven