George Arthur Brethen (born August 29, 1877 in Norwood, Ontario, Canada-died January 31, 1968) was a Canadian politician and farmer.
He was elected to the House of Commons of Canada as a Member of the Progressive Party in the 1921 election to represend the riding of Peterborough East.
He was defeated in the 1925 election in the riding of Hastings—Peterborough.