The 1998–99 Liga Femenina de Baloncesto was the 36th edition of Spain's premier championship for women's basketball clubs.
It marked the competition's expansion from 12 to 14 teams.
[1] Celta de Vigo defeated CB Halcón Avenida in the play-offs' final to win its fourth title 17 years later.
[2] CD Ensino and CB Sandra Islas Canarias were the regular stage's champion and runner-up respectively, also qualifying for the championship play-offs.
On the other hand, CB Navarra and Canal Isabel II CD were relegated as the two bottom teams.