It happened on Sycamore Drive, near the Contra Costa County Fairgrounds, just before 3:15 p.m. Monday.
The 14-year-old boy is expected to make a full recovery.
Bullet holes riddled several nearby vehicles.
Police don't know what led to the shooting.
Anyone with information about this shooting is asked to call Antioch police at (925) 778-2441. Anonymous tips may be sent via text message to 274637 with the key word ANTIOCH included in the message.