| Competition: | League of Ireland |
| Season: | 1938–39 |
| Winners: | Shamrock Rovers (6th title) |
| League Topscorer: | Patrick Bradshaw (22 goals) |
| Matches: | 132 |
| Total Goals: | 525 |
| Prevseason: | 1937–38 |
| Nextseason: | 1939–40 |
The 1938–39 League of Ireland was the eighteenth season of the League of Ireland. Shamrock Rovers were the defending champions.
Shamrock Rovers won their sixth title, and in doing so, became the first team to successfully defend their title.
Cork folded during the previous season, with Cork City taking their place.
| Team | Location | Stadium | |
|---|---|---|---|
| Bohemians | Dublin (Phibsborough) | Dalymount Park | |
| Bray Unknowns | Bray | Carlisle Grounds | |
| Brideville | Dublin (The Liberties) | Harold's Cross Stadium | |
| Cork City | Cork | Mardyke | |
| Drumcondra | Dublin (Clonturk) | Clonturk Park | |
| Dundalk | Dundalk | Oriel Park | |
| Limerick | Limerick | Markets Field | |
| St. James's Gate | Dublin (Crumlin) | St. James's Park | |
| Shamrock Rovers | Dublin (Milltown) | Glenmalure Park | |
| Shelbourne | Dublin (Ringsend) | Shelbourne Park | |
| Sligo Rovers | Sligo | The Showgrounds | |
| Waterford | Waterford | Kilcohan Park |