Grenville—Carleton was a federal electoral district in Ontario, Canada, that existed from 1968 to 1979. It was created from parts of the former Grenville and Carleton ridings for the 1968 federal election.
The riding encompassed a portion of eastern Ontario, generally including the townships of Oxford, South Gower, and Marlborough in Grenville County, and the townships of Osgoode, North Gower, and Nepean in Carleton County. This area included communities such as Kemptville, Manotick, and parts of what would later be incorporated into the city of Ottawa.
Grenville—Carleton was represented in the House of Commons for three terms. The first Member of Parliament was Walter Baker of the Progressive Conservative Party, who won the seat in 1968. Baker retained the seat in the 1972 and 1974 federal elections.
In 1979, the Grenville—Carleton riding was abolished and redistributed into the new ridings of Nepean—Carleton and Leeds—Grenville. Walter Baker successfully ran for re-election in Nepean—Carleton in the 1979 election.