People are likely to evaluate their group's standing on an ability dimension by comparing the performance level of their own group with that of an outgroup. However, in addition to contrasting performance outcomes, they may also compare the speci®c circumstances under which both groups have performed. From a related attributes perspective, we argue that the outcome of such a comparison is a crucial determinant of the extent to which the relative success or failure of one's group can be ascribed to its superior or inferior ability respectively, and hence of the degree to which the relative position of one's group on the performance dimension in question can be perceived as legitimate and stable (i.e. as justi®ed and unlikely to change). Accordingly, the present research shows that information concerning performance-related circumstances has an impact on a wide range of reactions to the relative performance of one's group, varying from the experience of positive and negative affect, to motivational responses such as changes in collective ef®cacy beliefs for performance improvement, individual effort on behalf of the ingroup, and the tendency to hinder the future performance of an outgroup. Copyright # 2002 John Wiley & Sons, Ltd.There could be no honour in a sure success, but much might be wrested from a sure defeat. (T. E. Lawrence) Although Festinger's (1954) theory of social comparison processes focused on the self-evaluative function of comparisons between oneself and another person (i.e. interpersonal comparisons), it is widely recognised that comparisons also arise in intergroup contexts (e.g. Goethals & Darley, 1987;Tajfel & Turner, 1979). That is, people may not only assess their individual ability by comparing their own performance with that of another person, but may also evaluate their group's ability by contrasting its performance with that of another group. Previous research on the consequences of such intergroup comparisons has predominantly focused on displays of ingroup favouritism in evaluative judgements or outcome allocations as a response to the relative position of one's group (see Mullen, Brown, & Smith, 1992 The primary goal of the present study, however, is to show that, in addition to comparing the performance level of their own group with that of an outgroup, people are also likely to compare the speci®c circumstances under which both groups have performed. This may reveal that the outgroup has been advantaged or disadvantaged relative to one's own group, because, for example, it had an easier or more dif®cult task to perform, or had different resources at its disposal. From a related attributes perspective (Goethals & Darley, 1977), we will argue that the relative advantage or disadvantage of an outgroup with respect to performance-related circumstances is a crucial determinant of the extent to which the relative success or failure of the ingroup can be ascribed to its superior or inferior ability respectively, and hence of the degree to which the relative position of the ingroup ...