There is a significant shortage of pediatric rheumatologists in the United States, and it is projected to worsen over the next several years. As a result, adult rheumatologists, despite having little to no training in pediatric rheumatology, care for an estimated 50% of children with rheumatic diseases. A major challenge to solving this problem is that we do not know how best to equip adult rheumatologists to take care of pediatric patients. This study addresses this gap by speaking directly to (1) families of pediatric patients who receive care from adult rheumatologists and (2) adult rheumatologists who care for children, in order to generate a rich understanding of their experiences. These interviews will provide physician and caregiver perspectives that will inform strategies at local, state, and national levels to improve the care that children receive from adult rheumatologists.