Sheriff's deputies responded to a report of multiple stabbings at the station at about 10:25 p.m. Saturday.
Arriving deputies learned that three people were stabbed on the light rail platform during a fight between two groups of passengers, according to the sheriff's office.
All three victims were transported to a hospital.
A 19-year-old woman was pronounced dead, according to the sheriff's office.
A 19-year-old man and 16-year-old girl underwent surgery for their stab wounds.
The sheriff's office is investigating the stabbing and encourages anyone with information to contact Detective Sgt. Herman Leon or Detective Sgt. Ryan Elder at (408) 808-4500. Callers wishing to remain anonymous can call the tip line at (408) 808-4431.