Despite evidence of widespread belief in conspiracy theories, there remains a dearth of research on the individual difference correlates of conspiracist ideation. In two studies, we sought to overcome this limitation by examining correlations between conspiracist ideation and a range of individual psychological factors. In Study 1, 817 Britons indicated their agreement with conspiracist ideation concerning the July 7, 2005 (7/7), London bombings, and completed a battery of individual difference scales. Results showed that stronger belief in 7/7 conspiracy theories was predicted by stronger belief in other real-world conspiracy theories, greater exposure to conspiracist ideation, higher political cynicism, greater support for democratic principles, more negative attitudes to authority, lower self-esteem, and lower Agreeableness. In Study 2, 281 Austrians indicated their agreement with an entirely fictitious conspiracy theory and completed a battery of individual difference measures not examined in Study 1. Results showed that belief in the entirely fictitious conspiracy theory was significantly associated with stronger belief in other real-world conspiracy theories, stronger paranormal beliefs, and lower crystallized intelligence. These results are discussed in terms of the potential of identifying individual difference constellations among conspiracy theorists.