Joseph Alfred Ernest Roy (October 3, 1871 – August 17, 1928) was a Quebec lawyer, journalist, judge and political figure.

He represented Montmagny in the Legislative Assembly of Quebec from 1900 to 1908, and Dorchester in the House of Commons of Canada as a Liberal member from 1908 to 1911.

Roy was born in Saint-Vallier, Quebec in 1871, the son of small landowner Nazaire Roy, and studied at the Séminaire de Québec and the Université Laval.

He articled with Adélard Turgeon and also later served as his legal secretary.

He was called to the bar in 1898 and set up practice at Quebec City, specializing in criminal law.