1966 All-Ireland Under-21 Football Championship
| Championship details | |
|---|---|
| All-Ireland Champions | |
| Winning team | Roscommon (1st win) |
| Captain | Colm Shine |
| All-Ireland Finalists | |
| Losing team | Kildare |
| Provincial Champions | |
| Munster | Kerry |
| Leinster | Kildare |
| Ulster | Donegal |
| Connacht | Roscommon |
The 1966 All-Ireland Under-21 Football Championship was the third staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964.
Kildare entered the championship as the defending champions.
On 2 October 1966, Roscommon won the championship following a 2–10 to 1–12 defeat of Kildare in the All-Ireland final. This was their first All-Ireland title.