To examine effects of the INSIGHT study responsive parenting (RP) intervention on reported and observed general parenting and child behavior during early and middle childhood. Primiparous mother-newborn dyads (n=279) were randomized to RP intervention or a safety control, with intervention content delivered at research nurse home visits at infant ages 3-4, 16, 28, and 40weeks and research center visits at 1 and 2years. At age 3 (n=220) and 6years (n=171) parenting and child behavior were observed during dyadic interactions and coded using the Iowa Family Interaction Rating Scales. Mothers also reported on child behavior (age 3) and aspects of general parenting (age 6) via the Child Behavior Checklist and The Comprehensive General Parenting Questionnaire, respectively. RP group children had fewer mother-reported externalizing (F=8.69, P=.004) and problem behaviors at age 3 (F=4.53, P=.03), and higher observed prosocial (F=4.73, P=.03) and lower antisocial (ie, externalizing; F=4.79, P=.03) behavior at age 6 vs controls. There were no study group differences in observed maternal sensitivity at age 3 or 6years. At age 6, RP group mothers reported higher use of structure defined by establishing consistent rules and routines (F=5.45, P=.02) and organization of their child's environment (F=7.12, P=.008) compared with controls. The INSIGHT RP intervention increased parental organization of the child's environment to facilitate competence, and had beneficial impacts on child behavior at 3 and 6years. No impacts were found on maternal sensitivity in childhood. ClinicalTrials.gov: NCT01167270.