Officers responding about 12:15 a.m. to a sideshow in the area of Russia Avenue and Paris Street found the three victims with gunshot wounds nearby, at Mission Street and Persia Avenue.
All three were taken to a hospital with life-threatening injuries and one has since died, San Francisco police Officer Robert Rueca said.
Police haven't confirmed whether the shooting is connected to the sideshow, and said it is part of the investigation.
No suspects have been arrested in the shooting, Rueca said.
Anyone with information is asked to contact the SFPD at 415-575-4444 or text at tip to TIP411 and start the message with SFPD.