Kalmthout (Dutch pronunciation: [ˈkɑl(ə)mtɦʌut]) is a municipality in the Belgian province of Antwerp.

[2] In addition to Kalmthout itself, the municipality also contains the communities of Dorp-Heuvel, Heide, Achterbroek, and Nieuwmoer.

The Kalmthoutse Heide is a nature reserve of nearly 10,000 acres (40 km2) spanning the border between Belgium and the Netherlands.

The Jewish community played an important part in local history, with the first Belgian yeshiva also being built in Heide.

Many architecturally innovative villas from the community still stand and can be seen during walking tours guided by local historians.