Pediatric subspecialists are critical to ensuring quality care and pursuing research to improve prevention, diagnosis, and treatment for children. However, there are substantial disincentives to pursuing a career as a pediatric subspecialist, which are often heightened for individuals from groups underrepresented in medicine, and more effective collaboration with primary care clinicians is needed. Changing health care needs, increasing care complexity, and access barriers to pediatric subspecialty care have raised concerns about the current and future availability of pediatric subspecialty care and research. In response, the National Academies, with support from a coalition of sponsors, formed the Committee on the Pediatric Subspecialty Workforce and Its Impact on Child Health and Well-Being to recommend strategies and actions to ensure an adequate pediatric subspecialty physician workforce to support broad access to high quality subspecialty care and a robust research portfolio to advance the health and health care of infants, children, and adolescents. This report outlines recommendations that, if fully implemented, can improve the quality of pediatric medical subspecialty care through a well-supported, superbly trained, and appropriately used primary care, subspecialty, and physician-scientist workforce.