Although the effect of low socioeconomic status on the health of adolescents has been documented, the mechanism by which this occurs is not well understood. Furthermore, improving adolescent health through public health policy typically requires the presence of one or more modifiable risk factors which can be targeted for intervention. In spite of the well-documented negative associations between poverty and health, few modifiable risk factors have been identified. This study used the Evans-Stoddart Model of Health and Well-Being as a framework to examine data on 1,759 adolescents, aged 12 to 19, collected as part of the 1994 National Population Health Survey. Results not only confirm the relationship between income and health, but suggest how the pathway operates through the social environment, lifestyle differences, access to health care, and a reduced sense of self-esteem and self-mastery. Bivariate and multivariate analyses found positive associations between physical activity levels and self-esteem and mastery. We interpret these findings as preliminary evidence that it might be possible to buffer the impact of poverty on health through policies which increase physical activity levels among those living in poverty. Such policies could also include a secondary goal of increasing the activity levels among inactive adolescents who are not living in poverty, as they will derive benefits from this increase, both psychologically and physiologically.