The sixth-seeded Tigers (15-15) blew an 11-point second-half lead. Alli Smalley's potential game-tying jumper at the buzzer glanced off the rim.
Diamber Johnson led 11th-seeded Mississippi State (13-16) with 16 points.
Smalley scored 14 points for the Tigers. Junior forward Chantel Hilliard had 18 points and 11 rebounds.
Auburn is likely to end up in the postsesason WNIT.