The 1998–99 League of Ireland Premier Division was the 14th season of the League of Ireland Premier Division. The division was made up of 12 teams. St Patrick's Athletic F.C. won the title. For sponsorship purposes, it was known as the FAI Harp Lager National League.

Regular season

The season saw each team playing three rounds of games, playing every other team three times, totalling 33 games.

Final Table

Results

Matches 1–22

Matches 23–33

Promotion/relegation play-off

Bohemians who finished in tenth place played off against Cobh Ramblers, the third placed team from the 1998–99 League of Ireland First Division. Bohemians won 7–0 on aggregate and retained their place in the Premier Division.