According to police Officer Esparza, the fight broke out aboard an inbound 14 Mission bus in the area of Mission Street and Precita Avenue at approximately 8 p.m.
It involved a group described as consisting of Hispanic males and females between 16 to 18 years old, Esparza said.
According to Esparza, the victim is a Hispanic man, 32 years old. He was transported to San Francisco General Hospital, Esparza said.
The conditions surrounding the stabbing are currently under investigation by police, who will be reviewing surveillance videos taken aboard the bus.
Anyone with related information can contact the Police Department anonymously at (415) 575-4444 or send a text message to (415) TIP-4111.