The Second Vatican Council (1962-1965) was an ecumenical council of Catholic bishops from around the world. The bishops made changes both in the internal life of the Church (e.g., the sacraments and daily practices of Catholics) and in the approach that the Church took toward other religions and toward the secular world. These changes transformed the mission of the Church. It is the purpose of this paper to examine how the mission of Catholic primary and secondary schools was transformed by this council. This paper is divided into three parts. The first is an analysis of the mission of these schools before Vatican II (1810-1962). The second is an analysis of Catholic school mission in the post-Vatican II era (1965-1995). The third part is a tool to aid reflection on the Catholic mission of one's own school.