Background: Teachers can play role models in following COVID-19 preventive measures and can act as supervisors ensuring students application of these measures. The practice of hand hygiene and mask use should be correct to achieve the desired effect. Objective: To assess the effect of health education intervention on Knowledge, Attitudes, Practices (KAP) of K-12 schools’ teachers as regards hand hygiene and mask use. Methods: Interventional study was conducted from March 2021 to July 2021 on 98 teachers from K-12 schools in Zagazig city, Sharkia Governorate, Egypt. Participants were given health education intervention including practical training and eliminating barriers to hand hygiene and mask use. The effect of intervention was assessed through KAP questionnaire and observation checklist. Results: Following intervention, the percent of participants who achieved satisfactory knowledge, positive attitude, satisfactory self-reported and observed practices related to hand hygiene had increased from 33.7%, 34.7%, 29.6% and 32.6% to 67.4%, 84.7%, 72.4 and 76.5% respectively and that related to face mask use had increased from 29.6%, 46.9%, 37.7% and 28.6% to 78.6%, 85.7%,72.5% and 69.4% respectively, most barriers to hand hygiene and face mask use had significantly decreased. Despite positive correlation between post intervention knowledge, attitudes and practices related to hand hygiene and mask use, there were insignificant associations between them and all participants characteristics except association of satisfactory observed practices with gender, marital state, and social class. Conclusion: Health education intervention was effective in improving knowledge, attitudes and practices related to hand hygiene and mask use among K-12 schools’ teachers.