The robbery occurred at a bank in the Sheppard Avenue East and Markham Road area on the afternoon of Nov. 23.
Police say one suspect carried a shotgun, while the other had a handgun.
According to police, the men wore balaclavas and gloves.
The man with the shotgun allegedly vaulted the bank counter and demanded staff get down on the ground.
A news release indicates that he demanded money from a teller and then "pushed the end of the shotgun into her lower back."
Police say the other suspect pointed his gun at the customers and the tellers.
The men fled with cash.
A 25-year-old Toronto man was arrested on Monday. Police allege he is the man who had the shotgun.
The accused is charged with robbery while armed with a firearm and using a disguise with intent.
None of the charges have been proven in court.
The second suspect remains at large.
Anyone with information is asked to contact investigators at 416-808-7350. Information can also be passed on anonymously through Crime Stoppers at 416-222-8477.