| Sint-Gillis-Waas | |
| Map: | Sint-Gillis-Waas East-Flanders Belgium Map.svg |
| Map-Legend: | Location of Sint-Gillis-Waas in East Flanders |
| Arms: | Blason ville be Sint-Gillis-Waas.svg |
| Flag: | Sint-Gillis-Waas vlag.svg |
| Arrondissement: | Sint-Niklaas |
| Nis: | 46020 |
| Pyramid-Date: | 1 January 2006 |
| 0-19: | 24.51 |
| 20-64: | 59.35 |
| 65: | 16.14 |
| Foreigners: | 2.78 |
| Foreigners-Date: | 1 July 2005 |
| Mayor: | Maaike De Ridder (CD&V) |
| Majority: | CD&V, Groen-Vooruit |
| Postal-Codes: | 9170 |
| Telephone-Area: | 03 |
| Coordinates: | 51.2167°N 11°W |
Sint-Gillis-Waas (pronounced as /nl/; fr|Saint-Gilles-Waes) is a municipality located in the Belgian province of East Flanders. The municipality comprises the towns of De Klinge,, Sint-Gillis-Waas proper and . On 1 January 2018, Sint-Gillis-Waas had a total population of 19,273. The total area is 54.98 km2 which gives a population density of 357 inhabitants per km2.