Dennis Murphy (April 2, 1842 – ) was an Ontario businessman and political figure. He represented Ottawa in the Legislative Assembly of Ontario as Conservative member from 1902 to 1904.
He was born in County Cork, Ireland, the son of J. Murphy, and was educated in Chatham, Argenteuil County, Canada East. In 1869, he married Annie Patterson. Murphy operated a business transporting goods on the Ottawa River.