"It's quite troubling that we can't afford comprehensive school counseling, but we can come up with the funds for weapons,"Anna Conklin, a child development specialist, said at the meeting.
The guns, which cost the department $14,000, did not require school board approval.
"I believe this was something that should have been brought to a board and for us to speak with the staff, the parents, just the community in general, find out from the cops why the guns are needed," said school board member Sophia Green.
School officials said the purchase was necessary to protect students at all 45 Fontana campuses.
"The police, they know where and how to handle the situations if anybody came on our campus, and you know, I'd rather be safe than sorry," said Dee Dee Arganda, a Fontana Unified School District teacher.
Assault rifles on school campuses are nothing new. Numerous local districts have them, but some parents say they fear for their children's safety and they question the use of the money.
"[The teacher] can't make copies for her kids for homework, but, yet again, they have money to buy these military-style riffles," said parent Virginia Nuno.
The school board couldn't discuss the purchase of the 14 Colt rifles because it was not on the agenda, but the topic is expected to be added to the next meeting.