Background: Lack of reproductive health education and sexual knowledge impacts the increasing number of sexual violence cases. From 2000-2018, in 161 countries and territories worldwide, nearly 30% of women were victims of sexual violence. Specifically, one of the sexual deviation behaviors is premarital sexual behavior. This behavior is the result of biological development, thus encouraging sexual desire. Thus, sex education is needed so adolescents can understand the importance of sex education and health. Objective: This study aims to identify the needs of adolescents in sex education. Methods: This qualitative research used the descriptive method. This study was conducted by in-depth interviews with five participants aged 12-15 years in Kalirandu Hamlet, determined by purposive sampling. The data validity test was carried out using member checking, thick description, and peer debriefing. In data analysis, this research utilized open code 4.03 software. In addition, this research has received an ethical license issued by the ethics committee of FKIK UMY, with No. 066/EC-KEPK FKIK UMY/III/2022. Results:The results of this study revealed the needs of adolescents in sex education, including the need for appropriate materials, media, and methods of delivering sex education. Conclusion: The process of adolescent growth and development in sex education needs to get more attention. The lack of knowledge of adolescents to get to the adult phase can cause the incidence of deviant sexual behavior. Therefore, adolescents need to know the need for sex education so that they do not violate norms and can protect themselves from deviant sexual behavior.