Building upon the social emotion model (Smith, 1999), we examined the combined impact of categorization context and social identification on emotional reactions and behavioural tendencies of people confronted with the victims of harmful behaviour. Depending on conditions, participants were led to categorize the victims and themselves in the same common group or in two distinct subgroups of the larger common group. We also measured participants' level of identification with the group that was made contextually salient. As predicted, emotional reactions of anger and their associated offensive action tendencies were more prevalent when participants were induced to see the victims and themselves as part of the same group and when they were highly identified with this common group. In line with appraisal theories of emotion, we also found that the emotional reaction fully mediated the impact of categorization context and identification on action tendencies. We discuss the data with respect to their implications for the role of emotion in improving intergroup relations.