Today intestinal worms still affect 1.5 billion people worldwide, mainly affecting the poorest communities in (sub)tropical countries. Today, the global response to reduce the morbidity attributable to these worm infections is limited to deworming school children only. Although large-scale deworming programs have made significant progress towards eliminating these worms as a public health problem, re-infection is perpetuating in absence of poor access to water, sanitation, and hygiene (WASH). In the past, school-led total sanitation (SLTS) has been implemented to improve WASH. SLTS is a multi-component intervention that trains children, teachers, and communities on how to improve the WASH conditions in schools and the surrounding area, but faces some important challenges that may impede implementation and acceptance. The aim of this proposal is to develop and validate an improved SLTS that leads to a more Positive, Liable, Usable, and Sustainable approach (SLTS-PLUS). In a first work package (WP), we will identify different options to improve WASH at schools together with key stakeholders (e.g., children and teachers). In WPs 2 and 3, we will further optimize the design of the SLTS-PLUS by iterating separate components, which will result in a comprehensive understanding of the needs and preferences of the community. In a final WP 4, we will assess both the impact and implementation of SLTS-PLUS, which will result in a proof of concept and practical implementation guideline.