This study aims to evaluate the effect of a game-based handwashing education program, which will be developed based on the Health Belief Model, on the handwashing behaviors of preschool children. Preschool children are considered more vulnerable to respiratory and gastrointestinal infections due to their immature immune systems and close contact with peers in school settings.

Within the scope of this project, a game called "Clean Hands" will be developed and a game-based handwashing education program will be implemented. The study will be conducted using a quasi-experimental pretest-posttest control group design with children aged 60-83 months attending two preschools with similar demographic characteristics. Children will be assigned to intervention and control groups.

Children in the intervention group will participate in the developed game as a group activity once a week for eight weeks. The control group will not receive any game-based intervention during the study period; however, the same game will be provided to the control group after completion of the intervention sessions.

Data will be collected using teacher observation forms, parent observation forms, handwashing step sequencing assessment forms, and handwashing behavior discrimination assessment forms. The findings are expected to contribute to the development of effective game-based health education strategies for preschool children.

Hand hygiene is considered an important health behavior in preventing infectious diseases among preschool children. However, establishing proper handwashing behavior as a sustainable habit in this age group can be challenging. Game-based learning approaches are considered effective methods for promoting health behaviors because they support children's active participation.

The "Clean Hands" game to be developed in this study will be structured based on the Health Belief Model. The game design will incorporate the components of perceived benefits, perceived susceptibility, self-efficacy, and cues to action. The game will include cards representing daily life situations, handwashing step sequencing activities, joker cards, and reward stickers. The intervention aims to help children both recognize situations requiring handwashing and correctly perform the handwashing steps.

The study will be conducted using a quasi-experimental pretest-posttest control group design. Children in the intervention group will participate in a group game session once a week for eight weeks. Before the intervention, children will receive a brief handwashing orientation, and short reminder activities will be used throughout the intervention process. No game-based intervention will be applied to the control group during the study period.

Data will be collected using teacher and parent observation forms as well as assessment tools evaluating children's handwashing behaviors. In addition, a follow-up assessment will be conducted after the intervention to evaluate the sustainability of the intervention effects.

Inclusion Criteria:

• Participation in at least 80% of the planned 8 game sessions (at least 7 sessions)
• Children aged 60-83 months enrolled in the preschool education institution where the research is conducted
• Children who have the cognitive ability to understand the given instructions and who do not have any physical condition preventing them from performing handwashing behavior
• Children for whom written parental consent for participation in the study has been obtained
• Children whose primary caregiver agrees to complete the parent observation form provided within the scope of the study, has Turkish literacy skills, and provides informed voluntary consent

Exclusion Criteria:

• Children outside the 60-83 months age range
• Children with a physical disability that may prevent them from performing handwashing behavior
• Children with cognitive impairments at a level that would make it difficult to understand the given instructions and actively participate in the game
• Children for whom written parental consent for participation in the study has not been obtained
• Children whose parents/caregivers do not agree to complete the parent observation form provided within the scope of the study, do not have Turkish literacy skills, or do not provide informed voluntary consent

Individual participant data could be shared in anonymized form; however, no formal data sharing plan has been established for this study.