Background The relative contribution of different pathways leading to health inequalities in adolescence was rarely investigated, especially in a cross-national perspective. The aim of the study is to analyse the contribution of psychosocial and behavioural factors in the explanation of inequalities in adolescent self-rated health (SRH) by family wealth in 28 countries.

Methods This study was based on the international WHO ‘Health Behaviour in School-aged Children’ (HBSC) study carried out in 2005/2006. The total sample included 117 460 adolescents aged 11–15 in 28 European and North American countries. Socioeconomic position was measured using the Family Affluence Scale (FAS). Multilevel logistic regression models were conducted to analyse the direct (independent) and indirect contribution of psychosocial and behavioural factors on SRH.

Results Across all countries, adolescents from low affluent families had a higher risk of reporting fair/poor SRH (OR1.76, CI 1.69 to 1.84). Separate adjustments for psychosocial and behavioural factors reduced the OR of students with low family affluence by 39% (psychosocial) and 22% (behavioural). Together, both approaches explained about 50–60% of inequalities by family affluence in adolescent SRH. Separate analyses showed that relationship to father and academic achievement (psychosocial factors) as well as physical activity and consumption of fruits/vegetables (behavioural factors) were the most important factors in explaining inequalities in SRH.

Conclusions More than half of the inequalities by family affluence in adolescent SRH were explained by an unequal distribution of psychosocial and behavioural factors. Combining both approaches showed that the contribution of psychosocial factors was higher due to their direct (independent) and indirect impact through behavioural factors.