The university has been without service since about 11 a.m. because of a power outage that affected 2,400 San Francisco customers, Pacific Gas & Electric spokeswoman Fiona Chan said.
The power outage affected areas south of Holloway Avenue to Randolph Street and between Capital Avenue and Beverly Street, Chan said.
It also affected the Lake Merced area, along Brotherhood Way between Lake Merced Boulevard to St. Charles Avenue, Chan said.
Power was restored to most by noon, and as of 4:30 p.m., there were 624 customers still without service, including SFSU, Chan said.
It was not clear when power would be restored. Chan said power could be restored sometime this afternoon.
PG&E is working with the university to notify students and staff about the outage, Chan said.
All classes on the school's main campus that were scheduled to begin at 4 p.m. or later have been canceled, and the downtown campus was not affected by the power outage.
Most business offices will remain open until their scheduled closing times. The One Stop Student Center planned to close at 5 p.m. instead of its normal closing time of 7 p.m.
There have been no reports of injuries or significant damage, university spokeswoman Ellen Griffin said.
This power outage is unrelated to the loss of service in Pacifica.