The present study investigated the relationship between delusion proneness, as assessed using the Peters et al. Delusions Inventory [Peters, E.R., Joseph, S.A., Garety, P.A., 1999. The measurement of delusional ideation in the normal population: Introducing the PDI (Peters et al. Delusions Inventory). Schizophr. Bull. 25 553-576], and cognitive insight, as assessed using the Beck Cognitive Insight Scale (BCIS; [Beck, A.T., Baruch, E., Balter, J.M., Steer, R.A., Warman, D.M., 2004. A new instrument for measuring insight: The Beck Cognitive Insight Scale. Schizophr. Res. 68, 319-329]. Two hundred undergraduate students with no history of psychotic disorder participated. Results indicated that, consistent with hypotheses, those higher in delusion proneness endorsed more certainty in their beliefs and judgment than those who were lower in delusion proneness (Self-Certainty subscale of the BCIS; p = .007). Contrary to hypotheses, however, those who were higher in delusion proneness were more open to external feedback and were more willing to acknowledge fallibility than those who were lower in delusion proneness (Self-Reflectiveness subscale of the BCIS; p = .002). The results are discussed in relation to theories of delusion formation.