Health is distributed unequally by occupation. Workers on a lower rung of the occupational ladder report worse health, have a higher probability of disability and die earlier than workers higher up the occupational hierarchy. Using a theoretical framework that unveils some of the potential mechanisms underlying these disparities, three core insights emerge: (i) there is selection into occupation on the basis of initial wealth, education and health, (ii) there will be behavioural responses to adverse working conditions, which can have compensating or reinforcing effects on health and (iii) workplace conditions increase health inequalities if workers with initially low socio-economic status choose harmful occupations and don't offset detrimental health effects. We provide empirical illustrations of these insights using data for the Netherlands and assess the evidence available in the economics literature. Copyright