Officials said the driver, Gilbert Armando Gonzales, 53, struck the two teenage boys on Beach Boulevard.
One teen was run over by the Chevy Astro Van; the other was trapped underneath an axle.
The first teen was transported by ambulance in critical condition to UCI Medical Center.
The second teen was removed from underneath the van and was airlifted in critical condition to UCI Medical Center.
The driver was also hospitalized, but in less severe condition, according to authorities. The driver was later arrested for suspicion of driving under the influence.
The incident remained under investigation. Anyone with information related to the collision was asked to call the Buena Park Police Department at (714) 562-3941.