Dominic Witter was arrested Thursday and is scheduled to be arraigned next week. Police say he sent sexually explicit pictures and text messages to a female student.
Witter, from Laguna Niguel, teaches at Crean Lutheran High School. Officials said he also coaches the school's girls' track and boys' soccer teams.
The 25-year-old was taken into custody after showing up at a pizza restaurant where he thought he would meet the victim. It turned out to be a police sting.
Investigators have notified the school about the arrest.
City News Service contributed to this report.