The suspect has been identified as 21-year-old Michael Escobar, a junior sociology major at the university. He's not a resident at the dorm.
A university spokesperson said at least four women reported that a man walked into their unlocked rooms in the Joe West dorm and touched them. The first report came in around 3:30 a.m. Friday.
Escobar was identified with the help of surveillance videos. He was arrested at an off-campus location for an unrelated case.
Authorities say none of the victims was injured or raped.
The incidents had prompted early-morning campus alerts. They came after two reports of gropings on or near campus in September. No one was arrested in those cases.
The Associated Press contributed to this story.