It happened on the Route 33 bus at 11:55 a.m. on Wednesday, May 17.
The video shows a large group of juveniles boarding the bus at 20th and Diamond streets in North Philadelphia.
Police say once on the bus, they immediately attacked passengers.
Police say one of the males repeatedly hit a passenger with a gun, causing it to fire and striking two 18-year-old victims in their legs. Both victims were taken to the hospital in stable condition.
The group then exited the bus and fled on foot.
Surveillance video shows SEPTA bus shooting
Police say the main suspect was between 14 and 17 years old and wearing a Bape brand hoodie.
Anyone with information should call the Philadelphia Police Shooting Investigations Group at 215-686-8271.