Emergency medical services (EMS) is defined as the system that organizes all aspects of care provided to patients in the pre-hospital or out-of-hospital environment. Hence, EMS is a critical component of the health systems and is necessary to improve outcomes of injuries and other time-sensitive illnesses. Still there exists a substantial need for evidence to improve our understanding of the capacity of such systems as well as their strengths, weaknesses, and priority areas for improvement in low-resource environments. The aim was to develop a tool for assessment of the pre-hospital EMS system using the World Health Organization (WHO) health system framework. Relevant literature search and expert consultation helped identify variables describing system capacity, outputs, and goals of pre-hospital EMS. Those were organized according to the health systems framework, and a multipronged approach is proposed for data collection including use of qualitative and quantitative methods with triangulation of information from important stakeholders, direct observation, and policy document review. The resultant information is expected to provide a holistic picture of the pre-hospital emergency medical services and develop key recommendations for PEMS systems strengthening.