The Cheltenham Township Police Department says the man stole an item from a Walmart located on 1000 S. Easton Road in Glenside back on November 4.
When confronted by an employee, he allegedly pulled out a gun and claimed to be a police officer.
The suspect then left in a white Chevrolet van and struck another car as he fled.
The suspect was last seen wearing a blue 76ers baseball hat and a light-colored "True Religion" sweatshirt.
If you have any information on the alleged impersonator, contact Cheltenham Township Police Department at (215) 885-1600 or call 9-1-1.