A multisource field study of 103 employees and their supervisors tested an extension of uncertainty management theory (E. A. Lind & K. Van den Bos, 2002; K. Van den Bos & E. A. Lind, 2002). According to this theory, persons high in social comparison orientation (F. X. Gibbons & B. P. Buunk, 1999) experience chronic uncertainty about the self. It was hypothesized that this should strengthen the effects of interactional and procedural justice perceptions on antisocial work behaviors. As predicted, the negative relationship between employee perceptions of interactional justice and supervisory ratings of antisocial work behaviors was stronger for people who are high as compared with low in social comparison orientation. Results provide evidence for an extension of uncertainty management theory to the self-domain.