This study examines the relationship between volunteer work and six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control, physical health, and depression. Using two waves of panel data from the Americans' Changing Lives survey (N = 2,681), the authors find that volunteer work enhances all six aspects of well-being. Conversely, people with greater well-being invest more hours in volunteer service. The study highlights the importance of considering both selection and social causation effects. While prior research has focused on the effects of voluntary memberships, this study emphasizes the reciprocal relationship between volunteer work and well-being. The authors argue that individuals' personal resources and well-being both facilitate their involvement in volunteer work and are subsequently enhanced by such work. The study also notes that the effects of volunteer work on well-being are robust even when controlling for other factors such as social integration and prior volunteer hours. The findings suggest that volunteer work can have positive effects on personal well-being, and that the relationship between volunteer work and well-being is bidirectional. The study concludes that understanding the mechanisms through which volunteer work affects well-being is important for developing effective interventions and policies.This study examines the relationship between volunteer work and six aspects of personal well-being: happiness, life satisfaction, self-esteem, sense of control, physical health, and depression. Using two waves of panel data from the Americans' Changing Lives survey (N = 2,681), the authors find that volunteer work enhances all six aspects of well-being. Conversely, people with greater well-being invest more hours in volunteer service. The study highlights the importance of considering both selection and social causation effects. While prior research has focused on the effects of voluntary memberships, this study emphasizes the reciprocal relationship between volunteer work and well-being. The authors argue that individuals' personal resources and well-being both facilitate their involvement in volunteer work and are subsequently enhanced by such work. The study also notes that the effects of volunteer work on well-being are robust even when controlling for other factors such as social integration and prior volunteer hours. The findings suggest that volunteer work can have positive effects on personal well-being, and that the relationship between volunteer work and well-being is bidirectional. The study concludes that understanding the mechanisms through which volunteer work affects well-being is important for developing effective interventions and policies.