Throughout its 40-year history, the Vlaams Belang (VB, Flemish Interest) has established itself as an important player within the Belgian party system, albeit with significant electoral fluctuations. In 2019, it became the second largest party in Flanders. The party developed and maintained a mass-party organisation by investing significantly in local party branches and in a rigid vertically articulated structure. It relies heavily on social media, particularly Facebook, to communicate to supporters beyond the more limited group of party members. Using both modern and traditional tools, VB representatives aim to create communities of supporters bonded to the party, facilitating dissemination of the party’s messages. Despite this investment in a grassroots organisation, the VB’s decision-making remains highly centralised. Social media and local branches allow informal consideration of members’ views, but the party has not created significant mechanisms for internal democracy. While it is often claimed that political parties have moved away from the “mass-party” model, this article demonstrates that the VB still maintains characteristics of the mass party, albeit with a modern twist. New social media tools facilitate attempts to foster communities and disseminate party messages among a wider group of supporters, both formal members and more informal sympathisers.