In this chapter we review evidence that self-affirmation (such as by reflecting on one’s important personal values) can facilitate more open-minded processing of health-risk information, mitigate adverse responses to stressors, and bolster well-being. We consider core mediators and moderators of effects and outline likely boundary conditions to the efficacy of applications of self-affirmation to health. Finally, we highlight issues relevant to the application of self-affirmation in real-world settings and suggest a number of key areas and research questions ripe for future investigation.