Ideological orientation may provide some citizens with an efficient heuristic for guiding their political judgment. Accordingly, one might expect that ideological uncertainty would lead individuals to engage more deeply with the political domain in order to acquire a sufficient level of subjective certainty that the ideological orientation they have adopted is the “right” one. Given the inherent complexity and ambiguity of the political realm, however, we propose that ideological uncertainty should instead undermine political efficacy and interest, thereby motivating individuals to disengage and withdrawal from participating in electoral politics. Using both correlational and experimental methods, we conduct four studies on both convenience and representative samples in the context of two electoral contexts to test this hypothesis. Study 1 (N = 343) and Study 2 (N = 1054) demonstrate that ideological uncertainty covaries with reduced levels of political engagement and participation in the 2012 and 2016 U.S. Presidential Election, respectively. Study 3 (N = 170) and Study 4 (N = 798) replicate and extend the results of Study 1 and 2 by experimentally manipulating ideological uncertainty using an original and innovative false-feedback paradigm. We demonstrate the causal effect of ideological uncertainty on political engagement (independent of demographic variables, political knowledge, and ideological extremity and conviction), and find that it is particularly pronounced among individuals who reflect on the meaning of their political judgment and behaviors for their political orientation. Implications for political choice and behavior are considered.