Stress has been shown to deplete the self-regulation resources hypothesized to facilitate effective role functioning. However, recent research suggests that positive affect may help to replenish these vital self-regulation resources. Based on the revised Stress and Coping theory and the Broaden-and-Build theory of positive emotion, three studies provide evidence of the potential adaptive function of positive affect in the performance of roles for participants experiencing stress. Participants were students (Study 1), caregivers of children with illness (Study 2), and individuals recently diagnosed with HIV (Study 3). In cross-sectional analyses, using role functioning as an indicator of self-regulation performance, we found that positive affect was significantly correlated with better self-regulation performance, independent of the effects of negative affect. The effects were not as strong longitudinally, however, and there was little evidence of a reciprocal association between increases in positive affect and improvements in role functioning over time. The results provide some modest support for hypotheses stemming from the Broaden-and-Build model of positive emotion and revised Stress and Coping theory, both of which argue for unique adaptive functions of positive affect under stressful conditions. Copyright © 2012 John Wiley & Sons, Ltd.