The Rancho Cucamonga Police Department arrested Chad Miller, 38, on Wednesday.
He's accused of reaching out to the teen through social media in April, and meeting up with her in person at multiple locations in Rancho Cucamonga for sexual encounters, police said.
Miller is a teacher at Canyon Oaks High School and police believe there could be more victims.
The Altadena man was booked at the West Valley Detention Center and his bail was set at $100,000. He is scheduled to appear in court on Friday.