Clinical reasoning is considered a core competency of physicians. Yet there is a paucity of research on clinical reasoning specifically in emergency medicine, as highlighted in the literature.We conducted a scoping review to examine the state of research on clinical reasoning in this specialty. Our team, composed of content and methodological experts, identified 3,763 articles in the literature, 95 of which were included.Most studies were published after 2000. Few studies focused on the cognitive processes involved in decisionmaking (ie, clinical reasoning). Of these, many confirmed findings from the general literature on clinical reasoning; specifically, the role of both intuitive and analytic processes. We categorized factors that influence decisionmaking into contextual, patient, and physician factors. Many studies focused on decisions in regard to investigations and admission. Test ordering is influenced by physicians' experience, fear of litigation, and concerns about malpractice. Fear of litigation and malpractice also increases physicians' propensity to admit patients. Context influences reasoning but findings pertaining to specific factors, such as patient flow and workload, were inconsistent.Many studies used designs such as descriptive or correlational methods, limiting the strength of findings. Many gray areas persist, in which studies are either scarce or yield conflicting results. The findings of this scoping review should encourage us to intensify research in the field of emergency physicians' clinical reasoning, particularly on the cognitive processes at play and the factors influencing them, using appropriate theoretical frameworks and more robust methods.