Inadequate sanitation is a significant risk factor for diarrhoeal disease and enteric infections, and is predicted to cause 280,000 deaths globally per year. Achieving sustainable sanitation changes at household level is a particularly difficult undertaking, with increasing understanding of the complexity, time, resources and effort required to achieve the global targets. This case study aims to synthesise and analyse outcomes of sanitation interventions across Timor-Leste, in terms of both uptake and sustainability, using a mixed-methods approach. Specific aims are: 1. Describe approaches to improved sanitation that are currently being implemented in Timor-Leste; 2. Examine the uptake and sustainability of sanitation interventions in Timor-Leste; and 3. Explore the opinions of WASH managers and field staff in Timor-Leste regarding different strategies to achieve improved sanitation, and perceived barriers and facilitators to uptake and sustainability of sanitation interventions.