World Vision’s FY21–25 water, sanitation, and hygiene (WASH) business plan calls for leveraging over $1 billion of investment for delivery of transformative WASH services to over 15 million people in 41 countries, mostly in fragile contexts, in partnership with governments, communities, and other organizations. However, progress toward meeting Sustainable Development Goal (SDG) 6 (clean water and sanitation for all) has been too slow, and many evidence gaps need to be addressed to effectively deliver such services. Therefore, World Vision is investing at least $5 million in implementation research during this period to better understand how to deliver transformative, sustainable WASH services, strengthen community norms and governance structures, and increase the well-being of the most vulnerable people globally.