According to the Social Identity model of Deindividuation Effects, intergroup comparison under anonymity accentuates social identity salience, potentially increasing motivation to work for one’s group. The present experiment aimed to examine whether intergroup comparison and anonymity could boost creative performance in a brainwriting task. Sixty participants, randomly assigned to groups, wrote their ideas on sticky notes of the same (anonymity) or different color (individuation). To reinforce social identity salience, half the groups were told that their performance would be compared with other groups. As predicted, anonymity and intergroup comparison boosted both the number of nonredundant ideas produced by group members (fluency), and diversity of ideas pertaining to different categories (flexibility). By contrast, when social identity was not salient, anonymity led to an increase in the originality of ideas.