Frontenac was the name of a defunct provincial electoral district in the province of Quebec, Canada.

It was located in the Estrie region, and is not to be confused with the existing Frontenac electoral district located in the Chaudière-Appalaches region, which re-used the name.

The 1966 version of Frontenac and the 1973 version of Frontenac were drastically different but actually had a small overlap of territory around the area of the modern municipality of Adstock.

It was created for the 1912 election from parts of the existing Beauce and Compton districts.

Its successor electoral district was Mégantic-Compton.