Antonian College Preparatory High School is an archdiocesan Catholic co-educational high school for students grades 9 through 12. Antonian has been recognized as a National Blue Ribbon Catholic high school. It is located in Castle Hills, Texas. It is located in the Roman Catholic Archdiocese of San Antonio. It was founded by the Order of The Christian Brothers in 1964 as an all-male Catholic high school. The school has been regularly included in the Action Institute's Catholic High School Honor Roll, a list of the top fifty Catholic high schools in America.