1980–81 Isthmian League

The 1980–81 season was the 65th in the history of the Isthmian League. Slough Town won the Premier Division, whilst Bishop's Stortford won Division One and Feltham won Division Two. The Isthmian League Cup was won by Enfield.
Premier Division
League table
Source:
Rules for classification: 1) points; 2) goal difference; 3) number of goals scored.
(C) = Champion; (R) = Relegated; (P) = Promoted; (E) = Eliminated; (O) = Play-off winner; (A) = Advances to a further round.
Only applicable when the season is not finished:
(Q) = Qualified to the phase of tournament indicated; (TQ) = Qualified to tournament, but not yet to the particular phase indicated; (RQ) = Qualified to the relegation tournament indicated; (DQ) = Disqualified from tournament.
Division One
League table
Source:
Rules for classification: 1) points...