ABSTRACT This project will iteratively develop and test a playable prototype of an interactive handwashing trainer to improve hand hygiene for students with disabilities in pre-vocational programs. The hand hygiene trainer will serve an unmet need to provide rigorous, systematic, and consistent instruction on proper handwashing technique. The interactive program will engage students, ensure that the training is to a high standard, and save teachers and staff significant time that would otherwise be spent on repetitive, 1-on-1 training. The commercially released trainer will be playable on smartphones, tablets, or notebooks, and will emphasize (1) how to wash--proper technique and duration; (2) when to wash--relevant scenarios and (3) consistent application-- establishment and maintenance of good hygiene habits. All three components are necessary for effective hand hygiene. Aim 1: Iterative Design. The project team will work with educational and prevocational experts as co-designers to develop a playable prototype for students with a range of physical and cognitive disabilities. Milestones: (1) concept check will ensure the training is accurate and appropriate. (2) Principles of universal design will build a trainer that ensures accessibility for a wide range of abilities (3) Hardware specs & testing will ensure the trainer runs on typical school hardware. (4) A teacher’s dashboard will track progress, identifying which students need attention. (5) Rapid iteration of quick development sprints, followed by playtesting, will accelerate prototyping to achieve a working prototype. Aim 2: Evaluation. Milestones: (1) A usability study with a teacher and students will test the playable prototype. (2) A feasibility study will test handwashing proficiency among students before and after the trainer intervention. This feasibility study will use single-case design. Single-case design studies are powerful, well-established approaches to assess learning interventions in educational and behavioral research. For special education students, who may exhibit wide variations in both type and severity of disability, the single-case design is particularly appropriate, because each subject serves as their own control. Repeated, careful measurements during baseline, followed by similar repeated measurements during intervention with the hand hygiene trainer, can detect changes due to the trainer, controlling for the variety of disabilities presented in the student population, as well as any potential improvement that may occur before the intervention is implemented. Potential for commercial applications include school-district and community-based pre-vocational programs, as well as large firms that commonly employ people with disabilities, and seek effective hand hygiene programs for their employees involved in healthcare support, food preparation, or sanitation.