Poor health and economic outcomes caused by a lack of adequate periurban sanitation are a growing global problem due to rapid urbanization in lowerand middle-income countries. While some interventions have been effective in improving rural sanitation, few have been tested in peri-urban settings, where poor infrastructure and the high prevalence of landlord-tenant shared on-site sanitation present a very different behavior change challenge. Previous trials have focused on providing subsidies, community mobilization, only attempted to create demand by sharing health benefit information, or have targeted only improved cleaning behaviors. However, previous work has demonstrated that improvements in sanitation quality may be effectively driven by other levers, such as emotional motivators, resolving information asymmetries, or improving the systems driving behavior. In addition, many programs have intervened on the demand and supply sides simultaneously, making rigorous evaluation of each component challenging. Though demand-side interventions alone are unlikely to be sufficient to attain full coverage of safely-managed sanitation, they may be a key component of more comprehensive programs. This thesis included formative research to build context-specific local knowledge about motivations, preferences, and social influences on sanitation quality; development of a composite measure of peri-urban sanitation quality; design of an intervention using a theory-driven creative process; assessment of tenant demand for sanitation using stated and revealed preference methods; and evaluation of the demand-creation intervention via a randomized, controlled trial. The papers that make up this thesis are the first of which we are aware to study shared sanitation improvement behaviors and processes through the lens of a behavioral science theory; develop and validate an outcome measure suitable to capture the overall quality of on-site sanitation; quantify tenant willingness to pay for improved sanitation quality; and generate rigorous evidence about the effectiveness of demand-side sanitation interventions in peri-urban settings across a range of behaviors of public health importance. This thesis demonstrates that a demand-side-only intervention can significantly improve sanitation quality in a peri-urban setting.