This article examines research evidence for the popular idea that humor and laughter have beneficial effects on physical health. Potential theoretical mechanisms for such effects are discussed first. Empirical evidence for beneficial effects of humor and laughter on immunity, pain tolerance, blood pressure, longevity, and illness symptoms is them summarized. Overall, the humor and laughter is less conclusive than commonly believed. Future research in this area needs to be more theoretically driven and methodologically rigorous.