We sought to determine impacts of a pediatric primary care intervention, the Video Interaction Project, on 3-year trajectories of parenting stress related to parent–child interactions in low socioeconomic status families. A randomized controlled trial was conducted, with random assignment to one of two interventions Video Interaction Project (VIP); Building Blocks or control. As part of VIP, dyads attended one-on-one sessions with an interventionist who facilitated interactions in play and shared reading through review of videotaped parent–child interactions made on primary care visit days; learning materials and parenting pamphlets were also provided to facilitate parent–child interactions at home. Parenting stress related to parent–child interactions was assessed for VIP and Control groups at 6, 14, 24, and 36 months using the Parent–Child Dysfunctional Interaction subscale of the Parenting Stress Index—Short Form, with 378 dyads (84 %) assessed at least once. Group differences emerged at 6 months with VIP associated with lower parenting stress at three of four ages considered cross-sectionally and an 17.7 % reduction in parenting stress overall during the study period based on multi-level modeling. No age by group interaction was observed, indicating persistence of early VIP impacts. Results indicated that VIP, a preventive intervention targeting parent–child interactions, is associated with decreased parenting stress. Results therefore support the expansion of pediatric interventions such as VIP as part of a broad public health strategy to address poverty-related disparities in school-readiness.