Toronto police, fire and paramedics rushed to the ferry terminal just after 5pm for the collision.
“There was a collision with the vessel as it docked and this caused several passengers to fall forward resulting in injuries,” Toronto police said.  Lori Cranenburg said.
The ship involved is the Sam McBride.  Cranenburg said there were 912 passengers and six crew members on board at the time of the incident.
Toronto paramedics said a dozen people suffered minor injuries, most of whom were later released.  Five people, including two children, were taken to hospital for treatment.
Acting Min.  Victoria Pfuetzner with Toronto Paramedic Services added that most of the injuries were to the knee.
Toronto Fire Chief Steve Buckingham said 10 of their appliances, including two fire boats, responded to the incident to help evacuate passengers and triage injured people.
The cause of the crash is unknown.
The Department of Labor and the Department of Transportation were notified.
“So right now, Toronto police are making sure the evidence is secure so that the investigation can begin and then there will be a discussion with the other agencies as to who will take the lead where,” said Duty Insp .  Cranenburg said.