The car, a newer-model Infiniti, was traveling southbound on the busy Jamboree Road in Newport Beach when it veered and hit a tree, said Newport Beach Police spokeswoman Kathy Lowe.
Four of the teens were thrown from the car and killed immediately, Lowe said, and the fifth person died at a hospital.
Orange County Sheriff's Department spokesman Jim Amormino said the victims were two boys and three girls, all from Irvine, but did not release any further details about their identities.
Officials are investigating the cause of the crash, including looking into whether excessive speed, drugs or alcohol were involved.
“That will be a part of our investigation to determine exactly the speed of the vehicle, what factors caused it to veer off the road and strike that tree,” Lowe said.