Background: Acne vulgaris (AV) is a multifaceted skin defect. It is the most popular skin disease, and it usually appears among preparatory school students. Aim: was aimed to assess risk factors of acne vulgaris in preparatory school students in Fayoum City. Research Design: A descriptive research design was used in this study. Setting: The current study was conducted from 49 preparatory schools in Fayoum City. Sample: A purposive sample was used to select 400 students diagnosed with acne vulgaris. Tools: the investigator used one tool: An interviewing questionnaire which consists of four parts patients socio-demographic data, Assess family past history and past medical history of preparatory school students diagnosed with acne vulgaris, preparatory students' knowledge regarding acne vulgaris, and risk factors that lead to acne are divided into hormonal factors, diet habits, hygiene habits, use of cosmetics products, sun exposure, and another habit. Results: This study showed, 48.5% of studied preparatory school students were in the age group 15 years, 65.0% of them were females, 40.25% of preparatory school students had average knowledge and 53.2% and 51.8% of students had a high level of risk factors about acne vulgaris related to hormonal factor and sun exposure factor, 46.8%, 44.8% and 56.7% of them had a moderate level of risk factors about acne related to dietary habits, personal hygiene, and other habits, 51.8% of them had a low level of risk factors about acne related to using cosmetics. Conclusion: There was a significant relationship between sexes with total risk factor levels. Additionally, it was a significant relationship between total risk factors level and student's family history of acne vulgaris. Recommendations: Periodic health education for community health nurses and school nurses about acne vulgaris that is helpful in early detection and management decrease those complications and improve preparatory school students' quality of life.