Joseph-Nestor Duguay (March 15, 1846 – March 17, 1907) was a businessman and political figure in Quebec.
He represented Yamaska in the Legislative Assembly of Quebec from 1874 to 1875 as a Conservative.
He was born in Baie-du-Febvre, Canada East, the son of Joseph Duguay and Anne-Scholastique-Olive Beauchemin, and was educated at the Collège de Nicolet.
Duguay was one of the pioneers of the dairy industry in the Yamaska region and owned a number of cheese-making facilities.