Theories suggest that identity motives for self-esteem, meaning, distinctiveness and belonging are implicated in intergroup discrimination. Experimental studies have supported predictions, but correlational tests have been hindered by methodological problems. Using a new approach to measuring identity motives, we compared predictions of individual differences in in-group favouritism. Seventy British adults completed measures of identity motives, British identification and positive and negative trait typicality ratings of British and German nationalities. With greater identification, the strength of motives for distinctiveness and belonging increasingly predicted in-group favouritism: consistent with optimal distinctiveness theory, the belonging motive predicted positive ratings of the national in-group, whereas the distinctiveness motive predicted negative ratings of the national out-group. Results show the value of disentangling measures of motive strength from measures of motive satisfaction.