2003 League of Ireland First Division
| Season | 2003 | 
|---|---|
| Champions | Dublin City | 
| Top goalscorer | Alan Murphy: 14 (Galway United) | 
| ← 2002–03  2004 →  | |
The 2003 League of Ireland First Division season was the 19th season of the League of Ireland First Division and the first to be played as a summer league.