Frontenac is a former provincial electoral district in the Chaudière-Appalaches region of the province of Quebec, Canada, which elected members to the National Assembly of Quebec.

As of its final election, it included the city of Thetford Mines and the municipality of Disraeli.

It is not to be confused with the pre-1973 Frontenac electoral district located in the Estrie region.

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 disappeared in the 2012 election and its successor electoral districts were the newly created Lotbinière-Frontenac and Mégantic.