1978 All-Ireland Under-21 Football Championship
| Championship details | |
|---|---|
| All-Ireland Champions | |
| Winning team | Roscommon (2nd win) |
| Captain | Séamus Hayden |
| All-Ireland Finalists | |
| Losing team | Kerry |
| Captain | Vincent O'Connor |
| Provincial Champions | |
| Munster | Kerry |
| Leinster | Louth |
| Ulster | Down |
| Connacht | Roscommon |
The 1978 All-Ireland Under-21 Football Championship was the 15th staging of the All-Ireland Under-21 Football Championship since its establishment by the Gaelic Athletic Association in 1964.
Kerry entered the championship as defending champions in search of a record-breaking fourth successive All-Ireland title.
On 15 October 1978, Roscommon won the championship following a 1-9 to 1-8 defeat of Kerry in the All-Ireland final. This was their second All-Ireland title overall and their first in 12 championship seasons.