Basilica of Our Lady of the Immaculate Conception is a Roman Catholic minor basilica and parish church in Guelph, Ontario, Canada. A Gothic Revival style building constructed between 1876 and 1888 by architect Joseph Connolly, it is considered Connolly's best work. The monumental church contains decorative carving and stained glass executed by skilled craftsmen. The church of Our Lady is one of the 122 parishes in the Diocese of Hamilton and currently has 2,600 families in the congregation.