| Competition: | League of Ireland |
| Season: | 1941–42 |
| Winners: | Cork United (2nd title) |
| League Topscorer: | Thomas Byrne (20 goals) |
| Matches: | 90 |
| Total Goals: | 366 |
| Prevseason: | 1940–41 |
| Nextseason: | 1942–43 |
The 1941–42 League of Ireland was the 21st season of the League of Ireland. Cork United were the defending champions.
Cork United won their second title, becoming only the second team to successfully defend their title.
Waterford resigned from the League voluntarily, resulting in a reduction in size from eleven to ten teams.
| Team | Location | Stadium | |
|---|---|---|---|
| Bohemians | Dublin (Phibsborough) | Dalymount Park | |
| Bray Unknowns | Bray | Carlisle Grounds | |
| Brideville | Dublin (The Liberties) | Harold's Cross Stadium | |
| Cork United | Cork | Mardyke | |
| Drumcondra | Dublin (Clonturk) | Clonturk Park | |
| Dundalk | Dundalk | Oriel Park | |
| Limerick | Limerick | Markets Field | |
| St. James's Gate | Dublin (Drimnagh) | Iveagh Grounds | |
| Shamrock Rovers | Dublin (Milltown) | Glenmalure Park | |
| Shelbourne | Dublin (Ringsend) | Shelbourne Park |