Purpose: The purpose of this study is to identify factors related to hand washing practice among adolescents beforeand after the outbreak of the COVID-19 pandemic. Methods: The study was conducted using data from the15th~16th (2019~2020) Korea Youth Risk Behavior Web-based Survey, and the subjects of the study were 57,303and 54,948 people who participated in the 2019 and 2020 study, respectively. The data were analyzed withfrequency test, rao-scott x2 test and multiple logistic regression analysis using SPSS 27.0. Results: Changes inthe hand washing practice rate were observed before and after the COVID-19 pandemic in all five behaviors;before eating in school, after using the toilet in school, before eating at home, after using the toilet at home, andafter returning home. The study found that the hand washing practice rate increased by 1.21-2.43 times after theCOVID-19 pandemic. In addition, as a result of logistic regression analysis, the hand washing practice rate beforeand after the COVID-19 pandemic was related to gender, region, school grade, school type, economic status,health status, and personal hygiene education experience. Conclusion: This study confirmed the importance ofhand washing education to improve the hand washing practice rate in adolescents. It is necessary to develop andapply an effective youth hand washing education program in consideration of various variables that appeared assignificant factors influencing the hand washing practice rate before and after the COVID-19 pandemic.