Water, sanitation, and hygiene (WASH) are fundamental to good health. However, in countries where WASH is underdeveloped, open defecation practices abound. Open defecation introduces fecal pathogens into the environment, and is associated with a variety of illnesses and disease. Community Led Total Sanitation is a participatory methodology that aims to ignite collective action in communities towards being open defecation free. However, the existing evidence on CLTS is mixed, thus necessitating further research into its effectiveness. This synthesis evaluation sought to systematically review the literature to answer two questions: 1) does CLTS eliminate open defecation?, and 2) what factors amplify or impede CLTS effectiveness? The aim of the research was to use a synthesis evaluation to compare CLTS interventions, and comment on the state of the evidence gap, if any. The results of the synthesis evaluation determined that it is difficult to state whether CLTS achieves its intended goals to eliminate open defecation. There are problems with open defecation free verification, and inconsistent measurement to determine cause and effect of the interventions. Factors which are important for CLTS success include leadership, cost effectiveness, geographic context, and the absence of subsidies. CLTS is often paired with complementary interventions, some which undermine CLTS success. CLTS interventions have limited protective effects against negative health outcomes, such as diarrheal prevalence. Moving forward, CLTS needs to be more robustly evaluated with experimental research designs. The evidence on leadership is promising, and worth more investigation. The nature of the evidence gap is large, and CLTS still needs to be studied in more depth.