| Lago Sul | |
| Settlement Type: | Administrative region |
| Official Name: | Região Administrativa de Lago Sul Administrative Region of Lago Sul |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Type2: | State |
| Subdivision Name: |  Brazil |
| Subdivision Name1: | Central-West |
| Subdivision Name2: | Federal District |
| Leader Title: | Regional administrator |
| Leader Name: | Rubens Santoro Neto |
| Established Title: | Established |
| Established Date: | 30 August 1960 |
| Area Total Km2: | 183.39 |
| Population Total: | 30175 |
| Population Density Km2: | auto |
| Timezone: | BRT |
| Utc Offset: | -3 |
| Coordinates: | -15.8428°N -47.8778°W |
| Area Code: | +55 61 |
| Postal Code Type: | Postal Code (CEP) |
Lago Sul (pronounced as /pt/; lit. South Lake) is an administrative region in the Federal District in Brazil. It is located on the south side of the eastern shore of Lake Paranoá, opposite of Brasília and Lago Norte. The Presidente Juscelino Kubitschek International Airport is located in the southwesternmost edge of the region.
Lago Sul is part of the Brazilian Highlands, with large amounts of cerrado vegetation.
Lago Sul has a tropical savanna climate (Aw in the Koppen Classification).