The Cathedral of Saint Mary of the Assumption, also known locally as Saint Mary's Cathedral, is the principal church of the Roman Catholic Archdiocese of San Francisco in San Francisco, California. It is the mother church of the Catholic faithful in the California counties of Marin, San Francisco and San Mateo and is the metropolitan cathedral for the Ecclesiastical province of San Francisco.

The cathedral is located in the Cathedral Hill neighborhood of San Francisco. The Cathedral of Saint Mary of the Assumption replaced one previous church (1891-1962) of the same name. The first original Cathedral of Saint Mary of the Immaculate Conception was built 1853-1854 and still stands today and is now known as Old Saint Mary's Church.