| All Ireland Champions | |
|---|---|
| Winners | Galway (5th win) |
| All Ireland Runners-up | |
| Runners-up | Offaly |
| Provincial Champions | |
| Munster | Tipperary |
| Leinster | Offaly |
| Ulster | Antrim |
| Connacht | Galway |
|
← 1990
1992 →
|
|
The 1991 All-Ireland Under-21 Hurling Championship was the 28th staging of the All-Ireland Under-21 Hurling Championship since its establishment by the Gaelic Athletic Association in 1964.
Kilkenny were the defending champions, however, they were beaten by Offaly in the Leinster final.
On 8 September 1991, Galway won the championship following a 2-17 to 1-9 defeat of Offaly in the All-Ireland final. This was their fifth All-Ireland title in the under-21 grade and their first in five championship seasons.