Leon Chang teaches at San Leandro High School. He turned himself into the San Jose Police Department Thursday.
The Alameda County District Attorney's office is charging him with two felonies.
Police say the relationship has been going on for some time.
Anyone with information regarding this case should contact the San Leandro Police Department's Criminal Investigations Division at 510-577-3230 or contact the Anonymous Tip Line at 510-577-3278.