Juliunn Redmond pitched in with 16 points and seven rebounds for ISU off the bench, while Tete Maggett contributed 13 points, eight rebounds and five assists.
Alexa Willard scored 16 points to lead five players in double figures for the Bears (17-3, 7-1). She made 7 of 11 shots from the floor.
Brice Calip totaled 15 points and eight assists for the victors, while Mya Bhinhar scored 14 off the bench on 5-of-10 shooting. Sydney Wilson added 13 points and five rebounds and Abby Hipp notched a double-double with 10 points and 11 boards.
Missouri State shot 54% from the floor, hit 8 of 17 from 3-point range (47%) and made all 15 of its free-throw attempts.