There is substantial evidence that health status and health outcomes are related to the availability and quality of personal relationships. The proposition that attachment relationships in childhood and adolescence have health-related implications fits within this research tradition, and has guided recent attempts to develop models linking attachment style with emotional regulation, coping mechanisms, and illness behaviours. The present paper discusses these theoretical models, together with relevant empirical findings. It is argued that measures of attachment security are related to symptom-reporting, health-care utilization, and restriction of normal activities, and that these links can be explained, in part, by individual differences in emotional and behavioural responses to stress. It is further noted that researchers have proposed physiological and biochemical pathways which may explain some of the effects of attachment style on physical health. The quality of parent–child attachment also predicts family responses to children’s illness, as reflected in parents’ visitation rates and in family participation in studies of health and illness. The implications of the findings for research and for practice in the health professions are briefly discussed.