Background: Child development is complex and definitions and categorizations are not universal. This can make a cohesive approach difficult for the many parties who have a responsibility to support and encourage development in young children in out-of-home care. In order to align policy priorities and simplify decision-making, it is perhaps more appropriate to take a holistic approach to child development, to recognize the interconnectedness of domains, and to promote development as inclusive and continuous. Objective: This presentation explores the developmental assessment of young children living in out-of-home care using the Ages and Stages Questionnaires® Third Edition (ASQ-3™; Squires & Bricker, 2009). Since 2016, the ASQ-3 has been integrated into the Assessment and Action Record (AAR-C2-2016; Flynn, Miller, & Desjardins, 2016), the core instrument of the Ontario Looking After Children (OnLAC) needs assessment and outcome monitoring project. Phase I of this study sought to examine and explain the relationship between the five domains of development measured by the ASQ-3 (communication, gross motor, fine motor, problem solving, and personal-social). Phase II aimed to provide decision-makers, including practitioners, caregivers, and policy-makers, with evidence of demographic, risk, and protective factors affecting overall development for children in care. Method: Phase I. We performed an exploratory factor analysis using a cross-sectional sample of 1,459 children aged eight months to five years living in out-of-home care in Ontario, Canada, in an attempt to further simplify ASQ-3 data and discover any underlying factors affecting subscale scores. Phase II. We conducted a 3-step hierarchical regression using a subsample of 1,097 children aged one to five years to examine the effect of possible predictors on overall development. Results: The factor analysis indicated that there was a single underlying construct reflected in the five ASQ-3 domains, which justified the creation of a composite score of overall development (α = .85). Higher scores on the composite measure indicate a higher level of overall development. The follow-up regression model was significant and explained 34% of the variance in overall development. Increased literacy-promoting activities, the child’s positive view of his/her abilities, and kinship placement were significant protective factors, and gender (male), social-emotional difficulty, and a higher number of other children living in the placement were significant risk factors. The child’s age was not a statistically significant predictor of overall development. Conclusion: The results of this study suggest that a simplified, holistic approach to child development is appropriate for use with young children in care. The domains of development measured by the ASQ-3 are tightly-tied; by promoting protective factors and addressing risk factors, decision-makers in a child’s life have the opportunity to positively shape his/her developmental outcome across all domains.