Objective <p>Populist attitudes and the tendency to believe in specific conspiracy theories (conspiracy beliefs) are often exploited by extremist or populist parties. However, more scientific research is needed to scrutinize this association. Consequently, the present non-preregistered exploratory online study assessed whether and how conspiracy beliefs and populist attitudes are associated and whether populist attitudes moderate the association between the preference for an analytical or intuitive thinking style and conspiracy beliefs.</p> Results <p>We assessed 483 nonclinical individuals regarding their conspiracy beliefs, populist attitudes, and thinking styles and found a moderate correlation between populist attitudes and conspiracy beliefs. Conspiracy beliefs were significantly predicted by three facets of populist attitudes (anti-elitism, preference for unrestricted popular sovereignty, and belief in the homogeneity and virtuousness of the people). Anti-elitist attitudes and a preference for unrestricted popular sovereignty significantly moderated (reduced) the impact of an analytical thinking style on conspiracy beliefs. Anti-elitism and a preference for popular sovereignty might enhance a person’s vulnerability to conspiracy beliefs. We assume that these populistic attitudes reduce a person’s motivation to use a more effortful thinking style to reinterpret ideology-inconsistent information to protect existing conspiracy beliefs. Our results provide new insights into the interplay between conspiracy beliefs, populism, and a preference for an analytical/more effortful thinking style.</p>