Verbum Dei High School students were on board the bus on Tuesday as it was traveling eastbound near Bellflower.
"At first, they thought something hit the bus, a rock or something. And when the coach came downstairs to talk to the driver... they realized that they got shot at," said Frank Gonzalez with Stardust Tours.
Three of the bus' windows were shattered in the shooting, but nobody inside was injured. The California Highway Patrol is investigating.
Windows shot out of 2 vehicles on 91 Freeway in Inland Empire, CHP says
Several similar shootings have been reported in recent weeks in Los Angeles and Orange counties, including on the 405 Freeway in O.C.
Gonzalez says repairs to the bus will cost around $8,000.
"This really hurts because this should be out today, bringing us some revenue and it's going to be here for a week now until it gets fixed," he added.
Gonzales says his business, Stardust Tours, has just reopened business after being shut down since last March, and now the damage to one of his best buses is setting him back even more.
"You've depleted your savings, you're trying to keep your business going and now we have to deal with this," he said.