A widely cited finding in social psychology holds that individuals with low levels of competence will judge themselves to be higher achieving than they really are. In the present study, I examine how the so‐called “Dunning‐Kruger effect” conditions citizens' perceptions of political knowledgeability. While low performers on a political knowledge task are expected to engage in overconfident self‐placement and self‐assessment when reflecting on their performance, I also expect the increased salience of partisan identities to exacerbate this phenomenon due to the effects of directional motivated reasoning. Survey experimental results confirm the Dunning‐Kruger effect in the realm of political knowledge. They also show that individuals with moderately low political expertise rate themselves as increasingly politically knowledgeable when partisan identities are made salient. This below‐average group is also likely to rely on partisan source cues to evaluate the political knowledge of peers. In a concluding section, I comment on the meaning of these findings for contemporary debates about rational ignorance, motivated reasoning, and political polarization.