Fire officials said the crash happened just before 12:30 p.m. at a Dunkin' Donuts in the city of Bethlehem.
Officials said it appeared that the driver was trying to park when the car accelerated and plowed through the front door, coming to rest next to the sales counter.
At least three adults and a youth were treated for injuries, but a fire department official said the injuries didn't appear life-threatening.
General manager Ragu Palli said the shop would be closed while damage is assessed.