Adilene Munguia was last seen Thursday at 3:35 p.m. boarding an MTA bus that was leaving the campus heading for downtown Los Angeles, university police said.
Munguia was supposed to meet her roommates Thursday night to go bowling, but she never showed up. The bio-chemistry major was last seen on the school's security cameras, walking across campus using her cellphone.
University spokeswoman Elena Stern says Munguia contacted her family after she learned her loved ones and the media thought she had disappeared.
She says it appears she was looking for some alone time and had shut off her cell phone.
"It apparently is a situation where she wanted to seclude herself and spend some time by herself, and so she voluntarily turned off her phone, and just sort of shut down and disappeared," said Stern.
The school is relieved she is safe and OK.
The Associated Press contributed to this report.