Bishop M. Thomas Shaw of the Episcopal Diocese of Massachusetts announced Tuesday that he will retire sometime ­after fall 2014, following two decades in office.

Shaw, 67, a quiet monk who became known for outspoken advocacy on economic and ­social justice issues, led the ­diocese through a turbulent ­decade in the Anglican Communion, during which controversy over the Episcopal Church’s first gay bishop and gay unions threatened to split the worldwide church and ­divided some congregations at home.