Background Low socio‐economic status (SES), post‐natal mental distress and parenting impact child mental health and future well‐being. There are unexplained differences in child mental health between South Asian ethnic minority groups living in the UK that may be due to variation in, and differential mediation of, these factors. Methods We used multivariate multiple regression analysis of the effect of symptoms of mental distress, socio‐demographic variables and warmth of parenting on child internalizing and externalizing scores at age seven (measured in 2010) in a population cohort of English children whose mothers were of Indian (n = 211) and Pakistani (n = 260) origin. Results In the fully adjusted models the legacy of mental distress was visible for both internalizing (β coefficient 1.52, P = 0.04) and externalizing (1.68, P = 0.01) behaviour in the Pakistani children, and on the Indian children's internalizing (2.08, P = 0.008) but not externalizing (0.84, P = 0.204) behaviour. Lower SES was associated with worse behavioural scores for the Pakistani children, and warmth of parenting on Indian children's externalizing scores. Conclusions Symptoms of post‐natal mental distress are associated with Indian and Pakistani child outcomes at age seven. The finding that warmth of parenting had a stronger association on Indian children's externalizing scores than mental distress might be explained by differences in the expression of SES on family characteristics and functioning between the two ethnic groups.