Toronto police say they were called to the Danforth Avenue and Broadview Avenue area at 1 a.m. ET.
Four injured people were found at the scene. The victims were all taken to hospital for treatment.
A 36-year-old man was arrested and charged with attempted murder, as well as three counts of aggravated assault. The accused is also charged with carrying a concealed weapon and with a dangerous weapons charge.
Staff Sgt. Ian Moyer told CBC News that investigators have yet to determine a motive for the attack.
Anyone with information is asked to contact police at 416-808-5500. Information can also be passed on anonymously through Crime Stoppers at 416-222-8477.