In a recent paper (Harris & Epton, Social and Personality Psychology Compass, 2009; 3, 962–978), we reviewed the evidence showing that self-affirming – the act of reflecting upon cherished values or attributes – can reduce resistance to health-risk information. In this companion paper, we extend the discussion of issues arising from that review and describe key questions for future research. Overall, we regard the picture emerging from this nascent literature as encouraging. Nevertheless, more needs to be discovered about how self-affirming achieves its effects and their limits. Despite lowering an important barrier to health behaviour change by reducing message resistance, there is currently only limited evidence that self-affirming changes subsequent health behaviour. We consider why. We also discuss issues to address in interventions involving self-affirmation and examine evidence that self-affirming alters relationships between variables. There is also scope for extending the range of samples, health information and health behaviours examined and for assessing more spontaneous self-affirmation.