The cyclist, 33, is in hospital with critical head injuries.
The incident happened at the corner of de Maisonneuve Boulevard and McGill College Avenue just before 9 a.m. on Thursday.
The cyclist was riding on the street when he approached McGill College.
Eyewitness Gregory Whiteside said cyclist was very close to an SUV when the driver honked.
"The SUV just swerved to the right, and that's when the cyclist fell," he told CBC Montreal. "I heard a huge crack. The cyclist wasn't moving at all. You could tell that something was really bad."
Police met with the driver Thursday afternoon to determine whether charges will be laid.