The shooting, reported at about 2:40 a.m., occurred in the 300 block of South 24th Street, San Jose police spokesman Ronnie Lopez said.
The victim had been talking to at least one person when the unknown suspect or suspects she'd been talking to shot her, according to Lopez.
Friends of the victim transported her to an area hospital where she was pronounced dead on arrival, Lopez said.
She is the city's fifth homicide victim this year. Her name has not yet been released.
Anyone with information about the shooting is urged to call the San Jose Police Department at (408) 277-5283.