['This paper presents a model that encompasses pathways and mechanisms working over adolescence that contribute to adult health inequalities. We review evidence on the four mechanisms: socially differential exposure, tracking, socially differential tracking, and socially differential vulnerability.', 'We conducted literature searches in English-language peer-reviewed journals using PubMed (from 1966 to May 2009) and PsycINFO, and combined these with hand-searches of reference lists, journals, and authors of particular relevance.', 'Most health indicators are socially patterned in adolescence and track into adulthood, with higher risks of adverse outcomes among individuals from lower socioeconomic positions. Adolescent health behaviours track into adulthood. Smoking, physical activity, and especially fruit and vegetable intake are socially patterned, while evidence for social patterning of alcohol use is less consistent. Relational dimensions like lone parenthood and bullying are socially patterned and track over time, and there are indications of a socially differential vulnerability to the effects of these types of relational strain. Very little research has investigated the social patterning of the above indicators over time or studied social vulnerability of these indicators from adolescence to adulthood. However, all four mechanisms seem to be active in establishing social differences in adult educational attainment.'] Do pathways and mechanisms in adolescence contribute to adult health inequalities?