The blaze was reported at 8:40 p.m. at Fratelli’s Italian Kitchen in the 3900 block of Mission Avenue.
Oceanside fire crews responded along with a crew from Carlsbad, Vista and Oceanside police.
People inside the restaurant reported seeing heavy smoke but did not see any flames.
Fire crews located flames inside a wall behind the pizza ovens.
Restaurant workers and customers were evacuated. No one was hurt.