The Sustainable WASH Systems Learning Partnership (SWS) is piloting factor mapping workshops to improve stakeholders’ understanding of complex WASH systems and align their perspectives on the key components and the interactions between them that lead to improved service delivery outcomes. Factor mapping is a type of focus group activity that enables participants to visually represent the interactions between different factors in a system. This brief outlines key steps in the factor mapping process and initial findings from its application in five locations in Ethiopia, Uganda, and Cambodia. Findings suggest that while WASH systems are comprised of similar parts, each system has unique connections between these parts. Outputs of the factor mapping process can help WASH practitioners identify strategic leverage points within a local system to target and inform systems-strengthening activities. The brief provides practical recommendations for the use of factor mapping in planning, implementation, monitoring and evaluation of WASH programs.