He succeeds David Henderson, who was fired after six years when the Blue Hens went just 9-21 overall this past season.
Ross, 33, spent the last 10 seasons as an assistant coach at St. Joseph's.
"We are excited to have Monte join the University of Delaware men's basketball program," said Athletic Director Edgar Johnson on the school's Web site. "During the interview process, we learned that Monte's contacts and success in recruiting young men from the Mid-Atlantic Region are truly superior. He knows the region and its players and coaches, our university, and the Colonial Athletic Association. Most important of all, Monte is a talented, personable, hard-working young man who has great rapport with his players. We are confident that he will bring the University of Delaware men's basketball program to prominence in the CAA."