Accurate triaging of patients in emergency departments (EDs) is crucial, since triage determines how quickly patients are assessed and treated. Understanding the factors that influence ED nurses’ triage decisions is important to ensure that patients are prioritised appropriately and cared for in a timely manner. This article reports and discusses the findings of a literature review on the factors that affect nurses’ triage decisions in the ED. Triage decisions by nurses in EDs are influenced by several factors relating to the patient, the nurse, the triage algorithm and the environment where triage takes place. Nurses’ ability to triage patients accurately is negatively affected by high patient numbers, inadequate staffing levels, lack of privacy and lack of training.