Background: Extreme desert heat (>40 degrees C) with heavy exertion during the Hajj mass gathering places elderly pilgrims with multiple comorbidities at elevated risk of heat-related illness (HRI); passive hydration advice alone has not resolved this burden.Objective: This review mapped evidence on the burden, risk factors, and prevention strategies for HRI among Hajj pilgrims, spanning behavioral, technological, and physiological approaches, and proposed a prevention framework for future testing.Methods: This scoping review followed PRISMA-ScR guidance. Peer-reviewed literature on Hajj heat illness and exercise-heat physiology published 2020-2026 was searched across PubMed/MEDLINE, Scopus, Cochrane CENTRAL, ScienceDirect, and Google Scholar, screened against an explicit PICOS framework, and synthesized narratively through inductive thematic coding.Results: Of 150 records identified through databases and 20 through citation searching, 65 duplicates were removed, 105 unique records screened, 57 reports assessed, and 20 sources met eligibility. Included sources documented substantial comorbidity and heat-illness burden among pilgrims, established risk factors including advanced age, cardiometabolic comorbidity, and limited prior heat acclimatization, and reported prevention approaches spanning education, cooling technology, and monitoring.Conclusion: Heat-related illness remains a major, multifactorial risk for Hajj pilgrims; an integrated framework combining education, conditioning principles, cooling technology, and monitoring warrants prospective testing before policy adoption.