The incident happened around 9 a.m. at 363 Bremner Boulevard, near Spadina Avenue and Lake Shore Boulevard.
Police say the man, who pulled out a gun during the robbery, had white paint over his face, while his lips were painted red.
He is described as being between five feet six inches and five feet eight inches tall, and was wearing a dark hoodie and green pants.
The suspect fled the scene on foot, but police are still investigating whether he got into a waiting car.
About half an hour after the robbery, police found a quantity of cash with a dye pack near Bellwoods Avenue and Dundas Street West.
Dye packs, which are designed to explode and stain bills with a bright red colour, are used by banks as a security measure.
It’s not clear how much money was taken.