| São Lourenço do Sul | |
| Settlement Type: | Municipality |
| Established Title: | Founded |
| Established Date: | 26 April 1884 |
| Pushpin Map: | Brazil |
| Pushpin Map Caption: | Location in Brazil |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Type2: | State |
| Subdivision Name: |  Brazil |
| Subdivision Name1: | South |
| Subdivision Name2: | Rio Grande do Sul |
| Leader Title: | Mayor |
| Leader Name: | Rudinei Harter (PDT); (2017–2020) |
| Area Total Km2: | 2036.125 |
| Population As Of: | 2020 [1] |
| Population Total: | 43,540 |
| Population Density Km2: | auto |
| Timezone: | BRT |
| Utc Offset: | -3 |
| Coordinates: | -31.3673°N -51.9795°W |
| Postal Code Type: | Postal Code |
| Postal Code: | 96170-000 |
| Website: | http://www.saolourencodosul.rs.gov.br/ |
São Lourenço do Sul is a Brazilian municipality in the state of Rio Grande do Sul. The municipality had 43,111 inhabitants in the last Census (2010). Its population in 2020 was estimated in 43,540 inhabitants. It is located at the west bank of the big lagoon Lagoa dos Patos.
The municipality contains part of the 7993ha Camaquã State Park, created in 1975.