To what extent are populist attitudes and conspiracy mentality two distinct constructs? While extensive research has explored the antecedents and effects of populist attitudes and conspiracy mentality individually, how these two concepts relate to one another has received limited attention. Existing studies suggest a positive association between these two concepts, yet it remains unclear whether these concepts represent distinct or similar psychological predispositions. This research note aims to assess the boundaries between populist attitudes and conspiracy mentality, arguing that while both share a Manichean outlook - perceiving the world divided into good and evil forces - they represent two empirically distinct concepts. Using exploratory, network and confirmatory factor analyses, we show that populism at the individual-level and conspiracy mentality are indeed two distinct, but related factors. The results further show a relatively weak overlap in a Manichean worldview. Additionally, we highlight notable differences in psychological and socio-demographic antecedents as well as in political preferences.