South Ayrshire (Scots: Sooth Ayrshire; Scottish Gaelic: Siorrachd Àir a Deas, pronounced [ˈʃirˠəxk aːɾʲ ə ˈtʲes̪]) is one of thirty-two council areas of Scotland, covering the southern part of Ayrshire. It borders onto Dumfries and Galloway, East Ayrshire and North Ayrshire. South Ayrshire had an estimated population in 2021 of 112,450, making it the 19th–largest subdivision in Scotland by population. With an area of 472 sq mi, South Ayrshire ranks as the 15th largest subdivision in Scotland.
South Ayrshire's administrative centre is located in its largest town, Ayr. The headquarters for its associated political body, South Ayrshire Council, is housed at the town's County Buildings, located in Wellington Square. Ayr is the former county town of the historic Ayrshire county, with the political activity of the Ayrshire County Council being based at County Buildings. From 1975 to 1996 under the name Kyle and Carrick (Scottish Gaelic: A' Chùil agus a' Charraig) it was one of nineteen local government districts in the Strathclyde region.