"No description, no location, no type, just that there was a bomb on campus," said Glendale Police Sgt. Tom Lorenz.
The anonymous call was made at about 8:30 a.m. After an extensive search of the campus, Glendale police gave the "all clear" just before noon.
Authorities say all 880 students were quickly accounted for and taken to the Whole Foods in the 300 block of North Glendale Avenue. A reverse-911 system helped alert parents to pick their children up.
Many parents, who were already on edge because of last month's Newtown shooting, picked up their children at the grocery store parking lot.
"It's very upsetting," said parent Pascale Vazquez. "You want the safety of your children because of what happened in Connecticut. We're going to need some time to actually settle down from that incident."