Traevon Jackson chipped in with 14 points and 11 rebounds for the Badgers (18-5, 5-5 Big Ten), who had lost back-to-back games coming into Tuesday's contest.
Nigel Hayes also had 14 for Wisconsin.
Rayvonte Rice led Illinois (13-10, 2-8) with 24 points and nine rebounds. Joseph Bertrand scored 11, but it was not enough to save the Illini from their eighth loss in a row.
Wisconsin led 36-30 at halftime; however Illinois lost its shooting touch with a 37-percent field goal average in the second half.