1998–99 New Mexico State Aggies basketball team

The 1998–99 New Mexico State Aggies basketball team represented New Mexico State University in the 1998–99 college basketball season. This was Lou Henson's 2nd season as head coach at his alma mater. The Aggies played their home games at Pan American Center and competed in the Big West Conference. They finished the season 23–10, 12–4 in Big West play to tie for the conference regular season title. They won the Big West tournament, and received an automatic bid to the NCAA tournament as No. 14 seed in the Midwest region.

In the opening round, New Mexico State was defeated by No. 3 seed and defending National champion Kentucky, 82–60.

Schedule and results
!colspan=9 style=| Regular season

!colspan=9 style=|Big West tournament

!colspan=9 style=|NCAA tournament