The International Classification of Diseases (ICD) is used to categorize diseases, injuries, and external causes of injury, and it is a key epidemiologic tool enabling storage and retrieval of data from health and vital records to produce core international mortality and morbidity statistics. The ICD is updated periodically to ensure the classification system remains current, and work is now under way to develop the next revision, ICD-11. It has been almost 20 years since the last ICD edition was published and over 60 years since the last substantial structural revision of the external causes chapter. Revision of such a critical tool requires transparency and documentation to ensure that changes made to the classification system are recorded comprehensively for future reference. In this paper, the authors provide a history of the development of external causes classification and outline the external cause structure. They discuss approaches to manage ICD-10 deficiencies and outline the ICD-11 revision approach regarding the development of, rationale for, and implications of proposed changes to the chapter. Through improved capture of external cause concepts in ICD-11, a stronger evidence base will be available to inform injury prevention, treatment, rehabilitation, and policy initiatives to ultimately contribute to a reduction in injury morbidity and mortality.