ABSTRACT Emerging empirical research and theory suggests that disparities in children’s early development and adjustment resulting from poverty and racism would be expected to be magnified in the context of the additional stressors engendered by COVID-19. However, there has been very limited study either of: 1) COVID-19 impacts on core psychosocial mechanisms likely to be shared with those of poverty and racism, including parent adjustment and parent-child relational health, or 2) the potential for increased resilience from preventive interventions delivered prior to COVID-19 that effectively target these core mechanisms. Building on extensive developmental and prevention research conducted prior to COVID-19, we developed an innovative, tiered birth to 3 year preventive model (Smart Beginnings [SB]) integrating universal, primary prevention delivered in health care (Video Interaction Project [VIP]) and targeted, secondary/tertiary prevention (Family Check-Up [FCU]) delivered through home visiting to facilitate population-level engagement and address heterogeneity in risk. SB has shown tremendous promise for both impact and scalability in an NICHD- funded (HD076390) randomized controlled trial (RCT) and ongoing competing continuation, with beneficial effects prior to COVID-19 on parent adjustment, relational health, and child psychosocial development. The proposed revision seeks to expand the scope of this ongoing RCT to address critical gaps in knowledge of impacts of COVID-19 for Latinx and Black low-income families (two groups that have been disproportionately affected by the pandemic), who were enrolled in New York City and Pittsburgh, PA, respectively. Enrollment (~200 per site, 403 total) and randomization took place shortly after birth, with follow-up assessments of parent adjustment, relational health and child development completed at 6, 18 and 24 months prior to COVID-19, and in progress at 4 and 6 years primarily following onset of the pandemic. In this revision, we will add detailed, remote assessments of COVID-19 family health and economic impacts at 2 time points following the onset of COVID-19 (quantitative at 9-12 months and qualitative/mixed methods at 18-24 months). Leveraging the SB cohort will provide a unique opportunity to critically examine: 1) the short and long-term impacts of COVID-19 on parent adjustment, parent-child relational health, and child development and adjustment across a continuum of family risk related to poverty and racism collected prior to COVID onset, and 2) potential buffering of SB on COVID-19 impacts, including in the context of race/ethnicity and family risk. Findings will provide generalizable knowledge necessary for design and scaling of interventions seeking to prevent potentially lifelong impacts of COVID-19 for highly vulnerable families of color with young children. In studying families who are among the most affected by the pandemic yet also among the most understudied, this revision is strongl...