Background: Although the ABC model proposed by cognitive behavioral theory has strong empirical support for a wide range of psychological problems, little is known about the role of irrational beliefs (IBs), a central concept of the ABC model, in the aetiology of paranoid thoughts, one of the most common psychotic symptoms. Aims: The present study aimed to investigate the impact of IBs on paranoid thoughts and people's perceptions of others. Method: Eighty-one non-clinical participants (m age = 21.21 years, SD = 2.72, range 18–33; 83.95% female) recruited for this study were randomly assigned to one of the two conditions: IBs or rational beliefs (RBs). In a role-play paradigm, subjects were asked to imagine holding a list of IBs or RBs, respectively, while being exposed to a neutral social context in a virtual reality environment. Results: In line with the ABC model, results indicate that IBs lead to significantly higher levels of state paranoid thoughts and more negative perceptions of others than RBs, even after controlling for participants’ baseline irrationality and trait paranoia [F (5,68) = 11.23, p < .001, Wilk's λ = .54, partial η2 = .45]. Conclusions: The findings of this paper suggest that IBs might play an aetiological role in the occurrence of paranoid thoughts. Practical and theoretical implications of these results are also considered.