The school made the announcement in a statement released Tuesday afternoon.
"The Xavier University Conduct Board (UCB), made up of faculty, students and administrators, found Xavier sophomore and basketball player Dezmine Wells responsible for a serious violation of the Code of Student Conduct. The punishment for the violation is expulsion from the University.
"While we understand there is heightened interest in this situation because it involves a student-athlete, we must reiterate that first and foremost Xavier's interest and responsibility to all of our students is to provide a quality education in a safe and nurturing environment.
"A serious violation of Xavier's Code of Student Conduct will not be tolerated. All Xavier students are subject to the same protections and consequences."
Xavier said it could not comment further on the nature of Wells' transgression due to federal privacy law restrictions.
The loss of Wells this close to the start of the 2012-13 season could not be a bigger blow for coach Chris Mack's team. A member of the 2012 Atlantic 10 All-Rookie Team, the 6-foot-5 guard averaged 9.8 points 4.9 rebounds per game during his freshman season at Xavier. He would have been the Musketeers' leading returning scorer and the likely focal point of Mack's offense.