Zemst () is a municipality located in the Belgian province of Flemish Brabant. The municipality comprises the villages of Elewijt, Eppegem, Hofstade, Weerde, Zemst-Laar, Zemst-Bos and Zemst proper. On January 1, 2024, Zemst had a total population of 23,401. The total area is 42.83 km<sup>2</sup> which gives a population density of 541 inhabitants per km<sup>2</sup>.