Politicization—the expansion of conflict in the political system—is often assumed to be associated with high levels of participation. Yet, this is not necessarily the case, especially in contexts of democratic backsliding. This study investigates how politicization of protest events affects individuals’ willingness to participate in protests, using Hungary as a most likely case. Three causal mechanisms are examined: perceived risks of participation, political efficacy, and public support. A pre-registered survey experiment conducted in August 2024 manipulates issue salience, polarization, and the number of actors involved. Findings show that increasing politicization leads to lower protest participation, driven primarily by reduced perceived political efficacy and expected public support.