This paper develops and tests a theory of the relation between health and SES over the life cycle; with the life-cycle model incorporating health, longevity, wealth, earnings, education, work, job-related physical and psychosocial health stressors, leisure, health and unhealthy consumption investment. The research found that higher SES, as measured by wealth, earnings and education, induces a healthy lifestyle. It also encourages investment in health, healthy consumption and discourages unhealthy consumption as well as protecting individuals from the health risks of physically and psychosocially demanding working conditions. The healthier lifestyle of high SES individuals causes the health trajectories of high and low SES individuals to diverge. As a result, they are healthier and live longer. In addition, health generates earnings and the worsening health of low SES individuals potentially leads to early withdrawal from the labour force. The paper details changes in the relationship between health and SES over the life cycle.