Résumé : Even though conspiracy theories are diverse, they are typically construed as a homogeneous phenomenon. Based on classic theorizations of conspiracy theories by Popper (1945; 2002) and Moscovici (1987), we propose to distinguish between belief in upward conspiracy theories (i.e., targeting relatively powerful groups) and downward conspiracy theories (i.e., targeting relatively powerless groups). The former are theorized as power‐challenging beliefs and the latter are theorized as being underpinned by conservative ideology. Across three studies conducted in Belgium (Total N = 2363), we show that these two types of conspiracy beliefs indeed relate differently to power‐challenging attitudes (i.e., political extremism, feelings of leadership breakdown) and conservative ideology. Specifically, upward conspiracy beliefs were characterized by a U‐shaped relationship with political orientation (i.e., an “extremism” bias), and a strong relationship with feelings of leadership breakdown. By contrast, downward conspiracy beliefs were strongly associated with conservative ideology. Both types of conspiracy beliefs were, however, positively correlated.