Systemic inequities persist within the pre-K system—as they do in many U.S. institutions—despite policy efforts to expand the supply of pre-K, invest in quality improvement initiatives, and prioritize enrollment for those who have been marginalized. This category includes, but is not limited to, children, families, and workforce members from Black, Hispanic/Latino, or Indigenous backgrounds; those experiencing poverty; those with disabilities or developmental delays; those who are immigrants; and those who are multilingual learners. This brief aims to describe the experiences of these specific groups of children, families, and workforce members (referred to as focal populations) that face inequities and discuss how a comprehensive pre-K data system can bolster ongoing efforts to ensure that all children experience the benefits of pre-K and that all families and workforce members are supported. These focal populations will be central to the development of a forthcoming System Transformation for Equitable Preschools (STEP Forward with Data) Framework through Child Trends’ Early Childhood Data Collaborative. (author abstract)