The man approached the child as the student was walking to Del Obispo Elementary School in San Juan Capistrano.
A composite sketch of the suspect was released.
Orange County Sheriff's deputies say he told the child to get into a truck, but the boy was able to run away.
The man was described as being in his 50s or 60s with short gray hair and a large nose.
His truck was described as a late-model gray Chevrolet pickup truck with a toolbox in the bed.
Anyone with information about the incident was urged to call the Orange County Sheriff's Department at (866) TIP-OCSD.