Authorities said the incident happened around 10:45 a.m. at a U.S. Bank inside a Vons grocery store in the 11800 block of Valley View Street.
The suspect is described as a man between 30 and 40 years old, 6 feet 1 inch tall, between 150 and 170 pounds. He has brown hair and a small goatee.
Authorities said the man entered the store, selected a shopping cart then a few moments later passed the bank teller a note demanding money. The teller gave the suspect an undisclosed amount of cash. He then fled the scene on foot.
Police also hope witnesses who were in the store and parking lot could come forward to provide more information.
Anyone with more information on the suspect was urged to contact Garden Grove police at (714) 741-5800 or contact the local FBI office.