The California Highway Patrol said the bike riders were traveling westbound on Mulholland Highway when they collided with an eastbound car turning left onto Stokes Canyon Road.
All three cyclists were transported to the hospital for treatment. The driver of the car, which was identified as an Audi A4, was not injured.
The CHP said there was no stop sign or traffic signal at the intersection.
Associated Press and City News Service contributed to this story.