John O’Brian (2 April 1944) is a Canadian art historian, writer, and curator.
He has taught at York University, Toronto, Harvard University, Cambridge, and Ritsumeikan University, Kyoto, as well as the University of British Columbia.
O'Brian is the author or editor of more than twenty books most of which focus on Canadian art and culture. His first book, David Milne and the Modern Tradition of Painting, published in 1983, was the first in-depth study of the artist.