State troopers responded to the scene, at I-405 and 160th Street, at about 4:40 a.m. after receiving a report of a body in the roadway.
The teen's body was found in one lane. He had been hit and run over by several vehicles that did not stop, the State Patrol reported.
Troopers say it appears the teen either jumped or fell onto the freeway from the 160th Street overpass. He was wearing a black sweatshirt, black pants and headphones.
His body was taken from the scene. His name was not released.