Aquinas High School is a co-educational institution accredited by the Western Association of Schools and Colleges and the Western Catholic Education Association. The Aquinas student experiences a traditional liberal arts curriculum that requires the pursuit of the college preparatory disciplines. The school works energetically to keep tuition affordable in the face of increasing costs each year. The school is deeply concerned that Catholic education is available to all students who could benefit and fulfill entrance requirements, without regard to the financial status of their household.

On June 15, 1954, Bishop Charles F. Buddy of the Diocese of San Diego (of which San Bernardino was then a part) announced Aquinas Hall would open the following academic year as a boys' Catholic high school. The school opened in 1955 with forty-nine freshmen. Bishop Buddy blessed the new facility on November 11, 1955. St. Bernadine's High School was an all-girl school, which closed its doors on its 50th anniversary in 1971. Its student body merged with Aquinas Hall, forming the co-educational Aquinas High School.

The 27-acre campus in located in a residential neighborhood north of State Hwy 210 between the Del Rosa and Highland Avenue exits. There are eight buildings, consisting of 23 classrooms, 2 science labs, 1 computer lab, library, chapel, school store, snack bar and counselors' offices, administrative and student support spaces. Athletic facilities include a gymnasium, football stadium with track, 2 locker rooms, tennis courts, and softball, baseball and soccer fields.

Aquinas High School is dedicated and committed to helping our students strive to do their best. Our Catholic tradition enables the entire community to develop and share a common vision. Our mission is simple: To form, through education, young men and women as leaders in the light and truth of the Gospel of Jesus.