Abstract
This thesis provides a description of socioeconomic differences in health related behaviour during differenct phases of the life course. Furthermore, individual characteristics and environmental factors are studied for their contribution to the explanation of these socioeconomic patterns in health related behaviour. DMHDS data provided information to describe and explain the relation between occupational level of the father and daily smoking and alcohol consumption during adolescence. Data from the Dutch longitudinal GLOBE study on socioeconomic health differences in the Netherlands enable the description and explanation of educational differences in (changes in) smoking, physical activity and alcohol consumption during childhood. Both studies collected extensive information on individual and environmental determinants of behaviour. Individual factors include personality, intelligence scores, attitudes or beliefs, and health. Environmental factors comprise psychosocial stressors, social support, social norms, financial situation, living environment, employment status, and deprivation. This thesis studied the role of these individual and environmental factors in the explanation of socioeconomic differences in health related behaviour and unhealthy behavioural changes.