The shooting happened just after 7 p.m. Monday on the 1600 block of West Highland Avenue.
Two men have been arrested in connection to the incident. Police said the suspects were found carrying the murder weapon.
Officials have not determined a motive.
The victims have been identified as 18-year-old Jesus Tiburiso, 19-year-old Ruben Sanchez and 20-year-old Evaristo Contreras.
All three of the victims were from San Bernardino.