Police received a call about a robbery at a TD bank branch in the Bloor Street West and Jopling Avenue area at 11:08 a.m.
They say the suspect had a handgun and passed a note to a teller.
He was given money that contains a dye pack, police say.
The suspect has left the branch. Police are now checking the area.
Anyone with information is asked to contact investigators at 416-808-2222.