John Cresswell Parkin CC OOnt RCA (24 March 1922 – 22 November 1988) was a British-Canadian architect who practised from 1944 to 1987 and worked predominantly in Toronto.

Parkin is credited as one of the leaders in the development of modern architecture in Canada during the post-war period.

Parkin took a job with the firm Marani and Morris, and Seidler with William Somerville.

The two Parkins decided to form a partnership but realized that the younger partner required additional design training.

Throughout the 1950s the firm acquired several large commissions including the Salvation Army National Headquarters, a new terminal at the Toronto Airport, and the Don Mills Shopping Centre.

By 1960, John B. Parkin Associates had grown to be the largest architectural firm in Canada.

On 1 January 1969, the firm merged with Smith Carter Searle Associates and became Parkin Architects Planners.