were the defending champions, having won the 1997–98 Omani League season.
emerged as the champions of the 1998–99 Omani League with a total of 34 points.
This season the league had 10 teams.
Quriyat Club and Buraimi SC were relegated to the Second Division League after finishing in the relegation zone in the 1997–98 season.
The two relegated teams were replaced by Second Division League teams Al-Suwaiq Club and Fanja SC.