Cape Breton South is a former provincial electoral district in Nova Scotia, Canada which existed from 1933-2013. It elected one member of the Nova Scotia House of Assembly. In its last configuration, the district included Sydney and its western suburbs until the North West Arm and south along the Sydney River until Blacketts Lake. The electoral district was abolished following the 2012 electoral boundary review and was largely replaced by the new electoral districts of Northside-Westmount, Sydney-Whitney Pier and Sydney River-Mira-Louisbourg.