It happened around 4 p.m. inside the Metro PCS store on the 200 block of E County Line Road in Warminster.
Police say two men robbed the store, then shot the male employee in the stomach.
Both suspects then fled out the rear of the store and ran east through the rear parking lot towards Newtown Road to a vehicle.
The victim is being treated at Abington Memorial Hospital.
Anyone with information is asked to contact Warminster police at (215) 672-1000.