The fire broke out around 11:30 p.m. Sunday at the New Golden Dawn Diner, located on Route 38 in Maple Shade Township.
Heavy fire was showing throughout the interior of the building when firefighters arrived.
Fire companies from surrounding areas responded to fight the fire. Crews broke out windows and ventilated the roof area before finally getting the fire under control.
There are no reports of injuries.
So far, authorities have not indicated what may have caused the fire.