It all happened around 11:30 a.m. in front of City College of San Francisco at Ocean Avenue and Phelan Avenue.
Sky7 HD captured the messy crash scene moments after it happened.
Muni officials say a vehicle was going fast when it rear-ended another vehicle just as it was turning.
The result was a white pickup truck with its tail in the air perched at a crazy angle on top of a sedan, smashing perpendicularly into the Muni bus.
Muni officials tell ABC7 News that the bus was stopped at the time, waiting at a red light. It had only a driver and one passenger onboard.
Neither were injured and the damage to the bus was minor.
The driver of the pickup is also okay. Two people in the crushed sedan, a man and a woman, were taken to the hospital.
A couple of other vehicles also got tangled up in the chain reaction crash, but no additional injuries were reported.
Muni was detoured for a while in the area, but reopened after crews checked the overhead lines and removed the wrecked vehicles.