Objective: The aim of this study is to determine the personal hygiene knowledge and health perception levels of adolescents and to evaluate the effectiveness of the training study. Materials and Methods: This study is an educationalintervention type research. Sample selection was not used in the study, and the sample of the study consisted of 326 female adolescents who answered the questionnaire questions. The data of the study were collected using the "Identification Form", "Personal Hygiene Information Form" and "Perception of Health Scale". Data collection was carried out in two stages. In the first stage, personal hygiene training was given to adolescents participating in the study, after the data collection forms were applied. The personal hygiene knowledge level of adolescents was evaluated with 30 information questions prepared by the researchers. In the second stage, personal hygiene knowledge levels of adolescents were measured again 4 months after the training. Results: The mean age of the adolescents was 15.99±1.15 years. It has been found that the level of personal hygiene knowledge is low in those with a history of any chronic disease, those who do not exercise regularly, and those who evaluate their health as bad. After the personal hygiene knowledge levels were determined, the students' level of personal hygiene knowledge increased significantly at the end of the informative study. Conclusion: Hygiene education given to adolescents has been effective in increasing their personal hygiene knowledge.