| Official Name: | Killay South Ward |
| Static Image Name: | Wm swansea killay south.jpg |
| Static Image Width: | 240px |
| Unitary Wales: | Swansea |
| Lieutenancy Wales: | West Glamorgan |
| Country: | Wales |
| Constituency Westminster: | Swansea West |
| Constituency Welsh Assembly: | Swansea West |
| Councillor1: | Jeffrey William Jones |
| Party1: | Liberal Democrats (UK) |
| Population: | 2,239 |
| Population Ref: | (2011 census) |
| Area Total Km2: | 1.24 |
| Hide Services: | yes |
Killay South (Welsh: Cilâ - De) was an electoral ward in the City and County of Swansea, Wales. The ward was mainly rural and consisted of some or all of the following areas: Dunvant, Ilston, Killay, Sketty and Upper Killay in the parliamentary constituency of Swansea West.
It was bounded by the wards of Dunvant and Killay North to the north; Sketty to the east; Mayals to the south; and Fairwood to the west.
For the 2012 local council elections, the turnout for Killay south was 43.73%. The results were:
| Candidate | Party | Votes | Status | |
|---|---|---|---|---|
| Jeffrey William Jones | Liberal Democrats | 429 | Liberal Democrats hold | |
| Peter Jones | Labour | 327 | ||
| Graham Coombs | Conservative | 111 |