Children with chronic illnesses present unique health, psychosocial, and learning challenges. Due to the complexities surrounding their needs, these children and their families often encounter multilayered barriers when accessing educational services and health care management. Medical-family-school interprofessional interagency collaborations (IIC) are needed to facilitate information sharing across institutions, treatment alignment among care partners, and equitable and high-quality school-based service delivery. This article presents a novel hospital-based school consultative liaison service, the Educational Achievement Partnership Program (EAPP), which conducts IIC with the families, schools, hospitals, and community care partners of children with chronic illnesses. We explore disproportionalities in IIC services among low-income and racially/ethnically minoritized children and examine ways to increase IIC service access and utilization. Results demonstrate that systematic changes targeting in-person communication with families significantly increased minoritized and low-income children's EAPP participation. Despite this increase, differences occurred between minoritized and White children's utilization through all stages of EAPP service delivery. These results underscore the importance of ongoing IIC service evaluation to examine the effectiveness of implementation components. We discuss implications and highlight opportunities for similar medical-family-school IIC under a school psychologist-led medical liaison consultative approach. We conclude that IIC is best fostered through innovations in communication models, graduate training, practice, and research.