Santa Margarita Catholic High School (SMCHS) is a coeducational college preparatory Roman Catholic high school located in Rancho Santa Margarita, California, United States. SMCHS is owned and operated by the Diocese of Orange, and was opened in 1987 under the direction of the Bishop of Orange. Although it follows the Catholic tradition, admission is open to students of all faiths. As of fall 2018, 1,673 students were enrolled in grades 9 through 12.