The paper examines the hypothesis that social inequalities in children's developmental resources level off during adolescence against an alternative hypothesis that they continue to exert their influence throughout all of childhood. Using data from the National Child Development Study, the study applies two models. Both are premised on the understanding that the social and physical environments in which children are raised affects their resources in the domains of educational achievement and psychosocial adjustment. A 'class inequalities' model seeks to determine the extent of social class inequalities at three key stages in children's development: the transition from infant to junior schooling at age 7, from primary to secondary education at age 11 and from compulsory education to further education or work at age 16. The second model is a contextual-systems model which seeks to expand our understanding of the pathways from family social class to children's educational achievement and psychosocial adjustment through some more proximal determinants of these resources: material deprivation, school composition, parental involvement and aspirations. Social class inequalities in educational achievement were found to be greater than inequalities in psychosocial adjustment. The same developmental pattern was observed for both outcomes: inequalities increased from age 7 to age 11 and then remained at the same level at 16 yr. The contextual-systems models showed that when social inequalities are interpreted more broadly than a narrow class based definition, they continue to widen in adolescence. In particular, family influences, indicated by parental involvement become less important and social contexts beyond the family, reflected in material conditions and school composition, become more important. At age 16, material deprivation was the strongest determinant of psychosocial adjustment while school composition was most strongly related to educational achievement. The contextual-systems model provides a more complete account of social inequalities in children's educational achievement and psychosocial adjustment than simple estimates of social class effects.