The Cathedral of St. John the Evangelist is the episcopal see of the Catholic Archdiocese of Milwaukee in Milwaukee, Wisconsin. The building itself is in German Renaissance Revival style, built in 1847, with changes after several fires. It is listed on the National Register of Historic Places and designated a Milwaukee Landmark. It is located just east of Cathedral Square Park.

The Archdiocese of Milwaukee is a Latin Church ecclesiastical territory, or archdiocese, of the Catholic Church in southeast Wisconsin in the United States.