Humanitarian interventions today are very different to those in the past. There has been a growing recognition of the central role that markets play in people's lives through giving them access to basic needs, jobs, and income generating opportunities. Based on the need to develop a rapid market assessment tool, Oxfam GB, the International Rescue Committee, and Practical Action, in consultation with other agencies, developed and piloted the Emergency Market Mapping and Analysis (EMMA) toolkit. Following an influx of refugees to Liberia fleeing from instability in neighbouring Cote d'Ivoire, the EMMA toolkit was used to understand specific market systems in depth, and the analysis used to design appropriate response options.