The Archdiocese of Boston is a Latin Church ecclesiastical territory, or archdiocese, of the Catholic Church in eastern Massachusetts in the United States. Its mother church is the Cathedral of the Holy Cross in Boston. The archdiocese is the fourth largest in the United States. As of 2023, the archbishop of Boston is Cardinal Seán Patrick O'Malley.

Seán Patrick O'Malley is an American cardinal of the Catholic Church serving as archbishop of the Archdiocese of Boston in Massachusetts since 2003. He is a member of the Order of Friars Minor Capuchin and was elevated by the Vatican to the rank of cardinal in 2006.