According to police, the man entered the Eastern Bank on Franklin Street at 2:30 p.m. on Monday and handed the teller a note demanding money.
The teller gave the suspect a sum of money and he fled in a car. According to police, the car appeared to be some type of SUV.
Police said the man showed no weapon and was wearing a green and white hat.
Anyone with information is encouraged to contact the Quincy Police.