The 1990–91 Lamar Cardinals basketball team represented Lamar University during the 1990–91 NCAA Division I women's basketball season. The Lady Cardinals were led by fifth year head coach Al Barbre. The team played their home games at the Montagne Center in Beaumont, Texas and were members of the American South Conference. The Lady Cardinals finished the season with a 29–4 overall and a 12–0 conference record. The team qualified for the 1991 NCAA Women's Division I Basketball Tournament winning games against Texas, LSU, and Arkansas. The team lost to eventual tournament championship game participant, Virginia in the Elite Eight.