Grey South was a federal electoral district represented in the House of Commons of Canada from 1876 to 1917.

The South Riding consisted of the Townships of Bentinck, Glenelg, Artemesia, Osprey, Normanby, Egremont, Proton and Melancthon.

The townships of Artemesia, Osprey, Proton and Melancthon were excluded from the south riding.

In 1882, the township of Artemesia and the town of Durham were incorporated into the riding.

The electoral district was abolished in 1914 when it was merged into Grey Southeast riding.