The 19-year-old woman was attacked by several men either late Saturday night or early Sunday morning, Santa Barbara County Sheriff's Office spokeswoman Kelly Hoover said.
The student was not sure where the attack happened, but it was either on the school's campus or in the neighboring community of Isla Vista, Hoover said. "The group acted together to commit the crime," the spokeswoman said.
The woman was able to return to her residence and tell her roommate. She was then taken to a local hospital for treatment.
There were no known witnesses, and the woman's name was not being released.
On Sunday, sheriff's deputies and UC Santa Barbara police appealed for the public's help.
"It's a very active investigation," Hoover said.