Belief in conspiracy theories about Jews is a prototypical example of how a naïve theory can serve as a universal explanation of "all the bad things happening in society." Such a theory often arises in times of political unrest that tend to breed feelings of uncertainty in politics and a lack of control over politics. As both uncertainty (a sense-making deficit) and lack of control (an agency deficit) can relate to conspiracy-based antisemitism, this research examines which of the two processes plays a pivotal role in the belief in Jewish conspiracy. Specifically, we hypothesize that political uncontrollability, rather than political uncertainty, is a critical factor in triggering conspiracy theories about groups. In Study 1 (N = 812) we found that lack of control, but not uncertainty, in the political domain predicted belief in Jewish conspiracy, and subsequently led to increased discriminatory attitudes toward Jews. The results of longitudinal Study 2 (N = 476) revealed that only political uncontrollability led to an increase in conspiracy-related stereotypes of Jews. In Study 3 (N = 172) we found that experimental induction of political uncontrollability increased belief in Jewish, German, and Russian conspiracy, whereas induction of political uncertainty did not. Finally, Study 4 (N = 370) replicated this pattern in another cultural context with more general measures of uncontrollability and uncertainty. It was lack of personal control, rather than uncertainty, that increased belief in Jewish conspiracy-and indirectly predicted other conspiracy theories. Our findings consistently support the critical role of political uncontrollability, not uncertainty, in triggering a conspiracy theory of Jews. (PsycInfo Database Record (c) 2020 APA, all rights reserved).