--- - |2+ Background While maternal depression is known to carry long‐term negative consequences for offspring, very few studies followed children longitudinally to address markers of resilience in the context of maternal depression. We focused on oxytocin (OT) and mother–child synchrony – the biological and behavioral arms of the neurobiology of affiliation – as correlates of resilience among children of depressed mothers. Method A community birth‐cohort was recruited on the second postbirth day and repeatedly assessed for maternal depression across the first year. At 6 and 10 years, mothers and children underwent psychiatric diagnosis, mother–child interactions were coded for maternal sensitivity, child social engagement, and mother–child synchrony, children's OT assayed, and externalizing and internalizing problems reported. Results Exposure to maternal depression markedly increased child propensity to develop Axis‐I disorder at 6 and 10 years. Child OT showed main effects for both maternal depression and child psychiatric disorder at 6 and 10 years, with maternal or child psychopathology attenuating OT response. In contrast, maternal depression decreased synchrony at 6 years but by 10 years synchrony showed only child disorder effect, highlighting the shift from direct to indirect effects as children grow older. Path analysis linking maternal depression to child externalizing and internalizing problems at 10 years controlling for 6‐year variables indicated that depression linked with decreased maternal sensitivity and child OT, which predicted reduced child engagement and synchrony, leading to higher externalizing and internalizing problems. OT and synchrony mediated the effects of maternal depression on child behavior problems and an alternative model without these resilience components provided less adequate fit. Conclusions Maternal depression continues to play a role in children's development beyond infancy. The mediating effects of OT and synchronous, mutually regulated interactions underscore the role of plasticity in resilience. Results emphasize the need to follow children of depressed mothers across middle childhood and construct interventions that bolster age‐appropriate synchrony. - Journal of Child Psychology and Psychiatry, EarlyView.