The social identity approach assumes that group members are internally motivated to adhere to group norms. Even though there is plenty of evidence for this assumption, research on how group norms translate into behavior is scarce. If ingroup norms are internalized, they should elicit the same effect as individual standards. Derived from research on internally motivated individual standards, it was predicted that discrepancies from group norms result in more negative affect, lower levels of well-being, and—based on self-completion theory—in compensatory effort in case of an opportunity to reduce the discrepancy. One correlational study and four experiments support these predictions. The results are discussed in relation to self-regulation approaches and the social identity approach. Copyright © 2011 John Wiley & Sons, Ltd.