Holsbeek is a municipality located in the Belgian province of Flemish Brabant. The municipality comprises the towns of Holsbeek proper,, and. On January 1, 2006, Holsbeek had a total population of 9,205. The total area is 38.50 km2 which gives a population density of 239 inhabitants per km2. A notable landmark in Holsbeek is the medieval castle of Horst, which is the fictional home of de rode ridder (the red knight).