| 1978 All-Ireland Under-21 Football Championship | |
| Bodyclass: | vevent |
| Headerstyle: | background:#BFD7FF; |
| Labelstyle: | white-space: nowrap |
| Datastyle: | white-space: nowrap |
| Header1: | Championship details |
| Label2: | Dates |
| Label3: | Teams |
| Header4: | All-Ireland Champions |
| Label5: | Winning team |
| Data5: | Roscommon (2nd win) |
| Label6: | Captain |
| Data6: | Séamus Hayden |
| Label7: | Manager |
| Header8: | All-Ireland Finalists |
| Label9: | Losing team |
| Data9: | Kerry |
| Label10: | Captain |
| Label11: | Manager |
| Header12: | Provincial Champions |
| Label13: | Munster |
| Data13: | Kerry |
| Label14: | Leinster |
| Data14: | Offaly |
| Label15: | Ulster |
| Data15: | Down |
| Label16: | Connacht |
| Data16: | 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.[1] This was their second All-Ireland title overall and their first in 12 championship seasons.
Semi-finals
Final