Arlington Catholic High School is a coeducational Catholic high school in Arlington, Massachusetts. It is located in the Roman Catholic Archdiocese of Boston, off of Massachusetts Avenue. Arlington Catholic High School was established in 1960 under the direction of Msgr. Oscar O’Gorman. It was built by the parishioners of St. Agnes Parish and opened as a regional high school staffed by the congregation of the Sisters of St. Joseph. Located in a suburban Boston community, the current student body represents 42 cities and towns in addition to the Town of Arlington. Enrollment in grades 9-12 is 791 students.