The fire broke out at about 3 a.m. at the Flap Jacks Restaurant in the 100 block of City Avenue in Bala Cynwyd.
Investigators say a paramedic driving by the restaurant spotted the fire and called 911.
When firefighters arrived, they encountered smoke and flames billowing from inside the restaurant. Fire officials say the fire started in the kitchen area and worked its way into the ventilation system.
It took firefighters approximately 30 minutes to place the fire under control.
The building sustained significant damage and is temporarily closed.
“As of now, the building’s closed. We have heavy damage in the kitchen area and the business will stay closed until further notice,” Deputy Fire Marshal Jim McCoy said.