University of Saint Mary of the Lake, also called Mundelein Seminary, is the principal seminary and school of theology for the formation of priests in the Roman Catholic Archdiocese of Chicago, governed from Chicago, Illinois in the United States. It is recognized as the first institution of higher education in the City of Chicago. Chartered by the Illinois General Assembly in 1844, it has the longest continuous academic charter in the state of Illinois. The Reverend Monsignor Dennis J. Lyle is the rector and president of the seminary and university. Cardinal Francis George, O.M.I., is the chancellor in his capacity as Archbishop of the Archdiocese of Chicago.

The largest major seminary in the United States, Mundelein Seminary serves 45 dioceses in eight different countries and was the first ecclesiastical faculty in the U.S.

In addition to the seminary, the University of St. Mary of the Lake offers the Lay Formation Program, Instituto de Liderazgo Pastoral, Diaconate Formation Program, and the Liturgical Institute.

Chicago Studies is an academic journal for priests and others in parish ministry. It is edited by the university/seminary faculty along with priests of the Archdiocese of Chicago.