Background: The paper examines the perception of stigma in 43 adults with an intellectual disability, the relationship this has with their psychological well-being and whether the process of social comparison has a moderating effect on this relationship. Materials and Methods: A questionnaire-based, within-participant design was used. Participants completed three self-report measures of perception of stigma, self-esteem and social comparison. Results: Perception of stigma was found to be significantly related to negative social comparisons, which in turn was significantly related to low self-esteem. No difference was found between social comparisons made with other service users and those made with people in the community. Social comparison was not found to have a moderating effect on the relationship between stigma and self-esteem. Conclusion: This study provides support for the influence of the perception of stigma and social comparison on the self-concept of individuals with an intellectual disability.