The PopulisTree is a taxonomy designed to explore the varieties of populism in Europe, both conceptually and empirically. Its accompanying datasets are available for both national elections and European elections. The PopulisTree was first introduced in an article published in European Union Politics.

While The PopuList, developed by Rooduijn and colleagues (2023), provides an authoritative overview of populist parties, it does not offer a systematic analysis of their ideological features. This gap motivated the creation of The PopulisTree, a tool crafted to fully explore the different varieties of populism in a simple, comprehensive, and systematic way.

The PopulisTree performs a detailed classification of how populist actors define the antagonism between “the people” and “the elites,” the essential dichotomy at the heart of populism (Mudde, 2004), and it identifies five main types of populist actors: populist right, populist left, populist agrarian, populist regionalist, and populist valence. Within the populist right and populist left, further sub-types are identified to capture more specific ideological configurations. Notably, The PopulisTree also provides a comprehensive list of populist radical right parties, which is not included in the overview by Rooduijn and colleagues (2023).

All labels in The PopulisTree consistently place the adjective “populist” first (e.g., populist agrarian rather than agrarian populist). This highlights that populism is typically secondary to other ideological features while ensuring terminological coherence across the taxonomy.

When using The PopulisTree, please refer to:

• The article introducing The PopulisTree: Zulianello, M. (2025). The PopulisTree: A Systematic Taxonomy and Dataset to Study Populist Parties in Europe. European Union Politics: https://doi.org/10.1177/14651165251395309
• And the dataset itself: Zulianello, M. (2025). The PopulisTree: A New Tool to Explore the Varieties of Populism in Europe. www.populistree.org. DOI 10.17605/OSF.IO/2KNGY