| Competition: | Athenian League |
| Season: | 1965–66 |
| Prevseason: | 1964–65 |
| Nextseason: | 1966–67 |
The 1965–66 Athenian League season was the 43rd in the history of Athenian League. The league consisted of 48 teams.[1]
| Competition: | Athenian League Premier Division |
| Season: | 1965–66 |
| Promoted: | None |
| Relegated: | Carshalton Athletic Hornchurch |
The division featured two new teams, both promoted from last seasons Division One:
| Competition: | Athenian League Division One |
| Season: | 1965–66 |
| Relegated: | Horsham Eastbourne |
The division featured 3 new teams:
| Competition: | Athenian League Division Two |
| Season: | 1965–66 |
| Promoted: | Croydon Amateurs Cheshunt |
| Relegated: | None |
The division featured 4 new teams: