Graft-versus-host disease (GVHD), either in its acute or chronic form, is the main contributory factor for morbidity and non-relapse mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recent advancements in the classification of this disease, with better applicability and reproducibility of standardized criteria, coupled with improvements in the management of steroid-refractory or resistant cases, have led to promising results. In 2020, the Brazilian Group for Pediatric Bone Marrow Transplantation of the Brazilian Society for Blood and Marrow Transplantation and Cellular Therapy (SBTMO) convened a task force to provide updated, evidence-based guidance for the diagnosis, classification, staging, prophylaxis, and treatment of GVHD, with a focus on the pediatric population, the results of which are presented here.