Northumberland—Peterborough South (French: Northumberland—Peterborough-Sud) is a federal electoral district in Ontario.

[2] Northumberland—Peterborough South was created by the 2012 federal electoral boundaries redistribution and was legally defined in the 2013 representation order.

It came into effect upon the call of the 42nd Canadian federal election, scheduled for 19 October 2015.

It contains the entirety of Northumberland County, southern Peterborough and the eastern half of the municipality of Clarington.

Ethnic groups: 89.8% White, 5.1% Indigenous, 1.2% Black, 1.1% South Asian Languages: 92.6% English, 1.3% French Religions: 54.1% Christian (17.6% Catholic, 11.3% United Church, 7.6% Anglican, 2.4% Presbyterian, 1.8% Baptist, 1.2% Pentecostal, 12.2% Other), 43.8% None Median income: $41,600 (2020) Average income: $53,100 (2020) This riding has elected the following members of Parliament: