Saint John XXIII High School is a Catholic independent, non-profit, coeducational, private day school which educates students in grades 9-12. The academic year consists of two semesters extending from approximately August to December and January to May in unincorporated Harris County, Texas, United States. Student leadership development through the Works of Ministries program is a distinct characteristic of each young person's college preparatory experience, and leadership principles are integrated into every course at Saint John XXIII. 'SJ' is accredited by/a member of the Roman Catholic Archdiocese of Galveston-Houston (RCAGH), led by Archbishop Daniel DiNardo.