This paper examines whether and how socio-economic status is associated with children’s behavioural development in today’s children. Using a large cohort of English children born in the early 1990s we find significant social inequalities in several dimensions of child behaviour at age 7. We examine whether these inequalities are associated with characteristics of the child’s early home environment and parental behaviours. These include the material quality of the child’s home, maternal mental health, parental conflict and child diet. Most of these factors are socially graded and so could potentially account for the gradient in behaviours, but none singly account for a large part of the gradient in behavioural outcomes. However, taken together, these differences in the home environment can explain up to half the social gradients in child behaviours.