Providing health care in times of complex emergencies (CEs) is one of the most vital needs of people. CEs are situations in which a large part of the population is affected by social unrest, wars, and food shortages. This systematic review study was conducted to identify the challenges of health-care delivery in CEs. We searched terms related to health-care delivery and CEs in PubMed, Web of Sciences, Science Direct, and Google scholar databases, as well as Persian databases SID and Magiran. The searching keywords included: “Health Care, Complex Crises, War, Humanitarian, Refugees, Displaced Persons, Health Services, and Challenges.” Of 409 records, we selected 6 articles based on the Preferred Reporting Items for Systematic Reviews (PRISMA) checklist. Studies were analyzed through qualitative content analysis. The results show that CEs affect health-care delivery in 4 primary areas: the workforce, infrastructure, information access, and organization of health services. These areas can pose potential threats for health-care providers and planners at times of emergencies. Thus, they should be informed about these challenges to strengthen the health-care system.