A number of theories and models of special relevance to individual health education are presented, such as: the Knowledge-Attitude-Practice model; Social Learning Theory and Health Locus of Control; the Health Belief Model; the Theory of Reasoned Action; and Bandura's Social Cognitive Theory. Recently, promising attempts have been made to integrate several of the models. Across the models, the most important regulatory factors for behaviour seem to be social norms, personal expectations and environmental reinforcements. These factors should be considered by the doctor in attempts to induce changes in patients' health-related behaviour. In the future development of health behaviour models, social and environmental factors will probably be given even more attention.