We examined the link between political engagement and the tendency to justify the sociopolitical system. On one hand, confidence in the system should be negatively related to political engagement, insofar as it entails reduced desire for social change; on the other hand, system confidence should also be positively related to political engagement to the extent that it carries an assumption that the system is responsive to citizens' political efforts. Because of the combination of these 2 opposing forces, the motivation for political engagement should be highest at intermediate levels of system confidence. Five studies revealed a negative quadratic relationship between system confidence and normative political engagement. In 2 representative surveys, Polish participants with moderate levels of system confidence were more likely to vote in political elections (Study 1) and to participate in solidarity-based collective action (Study 2). Two field studies demonstrated a negative quadratic relationship between system confidence and actual participation in political demonstrations (gender equality and teachers' protests in Poland; Studies 3 and 4). This pattern of results was further corroborated by analyses of data from 50 countries drawn from the World Value Survey: we observed negative quadratic relationships between system confidence and collective action as well as voting. These relationships were stronger in democratic (vs. nondemocratic) regimes (Study 5). Our results suggest that some degree of system confidence might be useful to stimulate political engagement within the norms of the system. (PsycINFO Database Record (c) 2018 APA, all rights reserved).