An 18-year-old woman was sexually assaulted on a TTC bus in the Markham Road and Lawrence Avenue East area on April 3.
Police say the woman was assaulted by a man who pretended to sleep. He fled the scene when the woman defended herself.
Police have described him as brown and approximately 50 years old, with black hair, brown eyes and a moustache.
Anyone with information regarding the incident is asked to contact police or Crime Stoppers.