Belgium is often portrayed as a textbook example of gradual federalization. Today, however, a rather new debate among political elites has emerged: whether torefederalize some of the powers that have been devolved to the substate entities. Yet, little is known about how citizens see the issue. The objective of this article is therefore to explore and compare citizens’ arguments for more or less regional autonomy. To this end, three citizen forums focusing on federalism were organized in 2017-2018: one in French, a second one in Dutch and a third one in German. They were transcribed and analysed using thematic analysis. Our results suggest that citizen opinions are justified based on two major argumentative themes: identity and efficiency. While one would expect the former to be of traditional importance, our analysis revealed that considerations about efficiency have taken the lead. This can above all be understood given the advanced stage of the Belgian federalization process, for which considerations of identity are still latently important but explicitly not sufficient enough anymore to justify further dynamics. Finally, our analysis also outlined the existence of additional argumentative frames related to path dependencies and the peculiar situation of Brussels.