The behavioural aspects of somatic symptom disorders have received minimal research attention to date. The first section of this paper identifies key theoretical perspectives relevant to behavioural responses to illness. Specifically, the sociological concept of illness behaviour is offered as a general framework in which to consider the range of psychosocial factors associated with responses to perceived illness. Further, the potential relevance of the construct of abnormal illness behaviour and the cognitive behavioural conceptualization of health anxiety is explored. The second part of the paper describes various approaches to the operationalization of illness behaviour, with particular emphasis on the Illness Behaviour Questionnaire, an instrument with a rich history of application. Additional insight is provided into two contemporary instruments which aim to measure overt behavioural aspects of illness more specifically. The third and final section of the paper makes recommendations for how future research may advance the understanding of state- versus trait-based characteristics of illness behaviour. Suggestions are made for how adaptive forms of behaviour (e.g. self-management, appropriate coping) may reduce the risk of developing a somatic symptom disorder or alternatively, minimizing the potentially negative psychosocial implications of such a presentation.