Milestones have been in effect for Accreditation Council for Graduate Medical Education-accredited hand surgery fellowships since 2015. In 2016, the Accreditation Council for Graduate Medical Education began an improvement process to make the milestones easier to read, understand, and assess. This article looks at the process used for hand surgery, makes comparisons between the two versions, and discusses the resulting changes. A representative group of hand surgery faculty and fellows worked together to review the milestones data and identify necessary changes. Working iteratively in large and small groups, the milestones were edited, and a supplemental guide was developed. The new hand surgery milestones have fewer patient care subcompetencies, yet include the same overarching themes. The medical knowledge subcompetencies have been reduced to four, and they now focus on key dimensions of knowledge development instead of pure anatomical knowledge. Systems-based practice, practice-based learning and improvement, professionalism, and interpersonal and communication skills include subcompetencies harmonized with all other accredited programs. Finally, the supplemental guide was created as an aid to clinical competency committees to provide clear understanding of the intent of the milestones. The guide includes examples for individual milestones, ideas for how to assess each subcompetency, and resources for faculty and fellows alike. The new hand surgery milestones were designed to be clearer and easier for clinical competency committees to evaluate and for faculty and fellows to understand. The accompanying supplemental guide is a new addition that will help individual programs better understand how to implement these changes. The new hand surgery milestones can be found at https://www.acgme.org/globalassets/pdfs/milestones/handsurgerymilestones.pdf.