William Critchlow Harris (30 April 1854 – 16 July 1913) was an English-born Canadian architect, primarily noted for his ecclesiastical and domestic projects in Maritime Canada.
He was born near Liverpool, England, to Welsh parents but moved to Prince Edward Island with his family as a young child.
He lived there most of his life; however, for much of the time, he led an itinerant existence, travelling throughout Prince Edward Island, New Brunswick and Nova Scotia, pursuing and executing design commissions across the region.
He was influenced by the Richardsonian Romanesque architectural style (for his domestic buildings) and Victorian gothic (for his church designs).
His greatest disappointment was the loss of a commission late in life to design the Anglican Cathedral in Halifax (1905-1910).