Starting in 2015, pediatric rheumatology fellowship training programs were required by the Accreditation Council for Graduate Medical Education to assess fellows' academic performance within 21 subcompetencies falling under six competency domains. Each subcompetency had four or five milestone levels describing developmental progression of knowledge and skill acquisition. Milestones were standardized across all pediatric subspecialties. As part of the Milestones 2.0 revision project, the Accreditation Council for Graduate Medical Education convened a workgroup in 2022 to write pediatric rheumatology-specific milestones. Using adult rheumatology's Milestones 2.0 as a starting point, the workgroup revised the patient care and medical knowledge subcompetencies and milestones to reflect requirements and nuances of pediatric rheumatology care. Milestones within four remaining competency domains (professionalism, interpersonal and communication skills, practice-based learning and improvement, and systems-based practice) were standardized across all pediatric subspecialties, and therefore not revised. The workgroup created a supplemental guide with explanations of the intent of each subcompetency, 25 in total, and examples for each milestone level. The new milestones are an important step forward for competency-based medical education in pediatric rheumatology. However, challenges remain. Milestone level assignment is meant to be informed by results of multiple assessment methods. The lack of pediatric rheumatology-specific assessment tools typically result in clinical competency committees determining trainee milestone levels without such collated results as the foundation of their assessments. Although further advances in pediatric rheumatology fellowship competency-based medical education are needed, Milestones 2.0 importantly establishes the first pediatric-specific rheumatology Milestones to assess fellow performance during training and help measure readiness for independent practice.