Informal backyard rentals (IBRs) constitute South Africa’s fastest growing housing subsector, flourishing within a relative research vacuum and without national policy intervention to address the vulnerabilities of stakeholders to the health risks potentially presented. This article reviewed the literature on IBRs, focussing on past policies and interventions, general characteristics, infrastructure and service access to inform an analysis of potential health risks from the existing literature to guide future research and policy-making. Research followed a qualitative approach to review IBR literature dating after 2004. Relevant publications were identified from bibliographic databases using Boolean search logic and by reviewing citations in and later citations of these publications. Relevant secondary sources were also included. The review evidenced that IBRs have received increasing policy, but limited research attention, and that health hazards have been particularly neglected. Although issues such as shared water and sanitation, inappropriate waste disposal, poor hygiene practices, high densities and poor quality structures have been referenced extensively – alluding to risks and health concerns – few studies have focussed directly on health, risk and vulnerability. The risk analysis completed based on the literature made potential risks explicit, exemplified by references to specific conditions, such as HIV/AIDS, tuberculosis and the coronavirus pandemic, demonstrating pathogenic pathways, contamination and transmission risks conducive to poor health, infection and potential disaster. The review captured and updated the contemporary literature on IBRs, with the subsequent analysis providing a platform for future empirical research on health, infrastructure and IBRs to address potential risks towards positive change in future policies.