| Competition: | Irish Premier League |
| Season: | 2003–04 |
| Winners: | Linfield 45th Irish title |
| Relegated: | Glenavon |
| Continentalcup1: | UEFA Champions League |
| Continentalcup1 Qualifiers: | Linfield |
| Continentalcup2: | UEFA Cup |
| Continentalcup2 Qualifiers: | Portadown Glentoran |
| Continentalcup3: | UEFA Intertoto Cup |
| Continentalcup3 Qualifiers: | Ballymena United |
| Matches: | 240 |
| Prevseason: | 2002–03 |
| Nextseason: | 2004–05 |
The 2003–04 Irish Premier League was the 103rd edition of the Irish League, the highest level of league competition in Northern Irish football. For this season there was a change from the structure of previous seasons, with the First Division reverting to intermediate status and the new Premier Division being renamed as the Irish Premier League. The league consisted of 16 teams, and Linfield won the championship.
Each team played every other team twice (home and away) for a total of 30 games.
Cliftonville, the club that finished in the relegation play-off place, faced Armagh City, the runners-up of the 2003–04 Irish First Division in a two-legged tie for a place in next season's Irish Premier League.
----Cliftonville won 4–1 on aggregate