The Diocese of New Westminster is an Anglican Church of Canada diocese in British Columbia, based in Vancouver. The current bishop is Michael Ingham. The diocese is comprised of the Regional Districts of Greater Vancouver, Fraser Valley, Sunshine Coast, Powell River and part of the Regional District of Squamish-Lillooet (including Squamish and Whistler).

There are two churches styled "cathedral" in the diocese; Christ Church Cathedral in Vancouver has been the cathedral since 1929. Holy Trinity Cathedral in New Westminster, now a parish church, was the cathedral from 1892 to to that date. Although no longer a cathedral, the Diocesan Synod allowed Holy Trinity to keep the title "cathedral" as a courtesy for historical reasons.

The diocese is at the centre of an international controversy within the Anglican Communion due to its decision to bless same sex unions. Several conservative provinces in the Communion, particularly those in Africa, have severed relations with the diocese over the issue which, along with the election of a gay bishop in New Hampshire, U.S., threaten to create a schism within Anglicanism.