We examined the effects of single-parent family status and high parental socio-economic status (SES) on the trajectories of children’s emotional/behavioural adjustment in early-to-middle childhood (ages 3-7 years). We also assessed whether these family characteristics interact with the equivalent neighbourhood characteristics of shares of single-parent families and high-SES adults in predicting these trajectories. Using data on 9850 children in England participating in the Millennium Cohort Study, we found that family status and parental SES predicted children’s trajectories of adjustment. Even after controlling for these family factors and key child and parent characteristics, the neighbourhood shares of high-SES adults and single-parent families were related (negatively and positively, respectively) to child problem behaviour. Importantly, children of low-SES parents in neighbourhoods with a high concentration of high-SES adults had fewer emotional symptoms than their counterparts in areas with fewer high-SES adults. Surprisingly, the adverse effect of single-parent family status on child hyperactivity was attenuated in areas with a higher share of single-parent families.