Taranaki Diocesan School for Girls ( formerly known as St Mary's Diocesan School, Stratford) is an all-girls Anglican secondary school in Stratford, Taranaki, New Zealand. Taranaki Dio has a boarding hostel, and the majority of the students at the school are boarders. In October 2018 St Mary's was renamed as Taranaki Diocesan School for Girls and the chapel rededicated to be known as the Chapel of St Mary.