Wellington South was a Canadian federal electoral district represented in the House of Commons of Canada from 1867 to 1968.

It was created by the British North America Act of 1867 as the "South Riding of the county of Wellington".

To the south riding were added consisted of the townships of Nichol and Pilkington, and the villages of Elora, Erin and Fergus.

In 1924, the riding was renamed "Wellington South" and was defined as consisting of the part of the county of Wellington lying south of the north boundary of the township of Pilkington, the north and east boundaries of the township of Nichol and the north boundary of the townships of Eramosa and Erin.

The electoral district was abolished in 1966 when it was redistributed between Halton, Wellington and Wellington—Grey ridings.