The present study tests both corollaries of the self-esteem hypothesis from social identity theory derived by Abrams and Hogg (1988). Greek students completed a pre-test collective self-esteem (CSE) measure and then rated Greek students and either American or Turkish students. They then completed a post-test collective self-esteem measure. Inconsistent with Corollary 2, higher prior CSE was associated both with higher in-group ratings and higher out-group ratings, but not with bias. Consistent with Corollary 1, change in CSE was positively associated with bias, positively associated with in-group ratings and negatively associated with out-group ratings. There were no differences due to type of out-group. The findings are consistent with the idea that, for specific comparisons between real groups, individual differences in self-esteem may affect the zone within which bias occurs rather than the amount of bias. However, achieving increases in self-esteem depends on establishing positive distinctiveness for the in-group in the context of a specific intergroup comparison.