Background: Personality dimensions such as openness and agreeableness have been found to be associated with prejudice levels towards several minority groups. Yet these variables have been mostly ignored by existing research into attitudes towards people with intellectual disability (PWID), which has primarily focused on contact and demographic variables. The current study investigated the relationship between personality dimensions and attitudes toward PWID. Methods: An online survey was completed by 466 adult participants recruited through a variety of sources. The survey consisted of a well-validated attitude survey, the Big Five inventory, contact related and demographic questions. Results: The hypothesis that higher levels of the personality dimensions openness and agreeableness would be significantly associated with positive attitudes towards PWID was supported. However the effect was relatively weak and the strongest predicting factor of positive attitudes was increased quality of contact with PWID. More positive attitudes were also associated with females, more highly educated and younger participants. Conclusions: Results provide support for an integrated (including person and situational factors) theoretical approach to attitudes research in this field. Practically, results support programmes that stimulate and promote quality interactions between PWID and the wider community. Â© 2015 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.