Knokke-Heist is a municipality in the Belgian province of West Flanders, situated along the North Sea in a polder area on the border with the Netherlands. It comprises the towns of Heist-aan-Zee, Knokke, Duinbergen, Ramskapelle, and Westkapelle. The location is characterized by its coastal setting within the Zwin region, which historically served as a strategic harbor before silting up.

The area was originally settled by shepherds and fishermen in marshy lands that were dewatered via dykes between the 11th and 13th centuries. Strategic importance grew during conflicts involving the Counts of Flanders and later English attacks, leading to fortifications and agricultural development. The territory saw annexation to the Netherlands after 1713 before returning to Belgian administration, with tourism development accelerating after the Leopold Canal was constructed in 1857.

The municipality includes the exclusive Royal Zoute Golf Club in the dunes and the Zwin coastal nature reserve, a protected bird sanctuary. Notable landmarks feature the Sincfala museum in Heist, various sculptures including works by Joep van Lieshout, and the pink fountain at the tourism center. The area is known for its art galleries and the remote Zwin Beach at the eastern end near the Dutch border.

Knokke-Heist hosts over 40 art galleries and the Kneistival music festival every July since 1986. Cultural events include the Experimental Film Festival, the Cartoon Festival, and annual carnivals in late February. The town also hosts the Belgian Basketball and Volleyball Supercups, as well as the Miss Belgian beauty pageant, drawing visitors for its diverse cultural and sporting calendar.

The population was 33,097 as of 2018, with a total area of 56.44 km2. Access is provided by the E34 motorway, the coastal tram line terminating at Knokke, and three railway stations offering connections to Bruges, Ghent, and Brussels Airport. The municipality is described as Belgium's most affluent seaside resort, attracting tourists for its beaches and golf clubs.