The injured person, who was not being identified, was riding a bike westbound on Geary beside a 38 Geary bus near Leavenworth Street when the car door opened at about 2:11 p.m., Muni spokesman Paul Rose said.
The bicyclist then turned to miss the door and the handlebars of the bike made contact with the side of the bus and the person fell down but apparently was not run over, Rose said.
The bike rider suffered unknown injuries and was transported to San Francisco General Hospital, according to the San Francisco Fire Department.