EDOMGENET MULUNEH,ZEBIBA ABDELA,REDIET ABEBE,2023-11-272023-11-272022-03http://10.194.1.109:8080/xmlui/handle/123456789/205Background- Sexually transmitted infections are a major health problem affecting mostly young people, not only in developing, but also in developed countries. It is an infection that has a significant probability of transmission between humans by means of human sexual behavior, including vaginal oral sex, and anal sex. More than 30 different bacteria, virus and parasites are known to be transmitted through sexual contact. According to the 2011 EDHS report, 63% of women and 56%of men who had an STI or STI symptoms did not seek any advice or treatment; this has a great impact on STIs prevalent in the country (12).The aim of this study was to assessed knowledge, attitude, preventive practice and associated factors on STIs. Objectives: To assess the knowledge, attitude, preventive practice on sexually transmitted infections and associated factors among students at Aba Franso preparatory school Gurage zone, SNNPR, Ethiopia, 2022 Methods –An institutional based cross- sectional study was conduct from March to June 2022.A total of 423 students was involved in the study using systematic random sampling technique. Data was collect using a structured self-administer questionnaire, the collected data was enter to EPI-data version 3.1 software and analyze using SPSS version 21. The descriptive result present in text, figure and table. P value of 0.05 and 95% confidence level was considered to be asserted statistical significance. Result-From the total 423 respondents 95% heard about sexual transmitted infection, majority of them get the information in friends. 46.1% of participant had good knowledge and 39% had favorable attitude. 44% had good preventive practice on sexual transmitted infection. Conclusion and recommendation- less than half of participant had good knowledge and less half of participant had favorable attitude and preventive practices. We would like to recommend Aba franso preparatory school director and other teacher members to organize and strengthen anti-Sexual transmitted infection club in school that focus on reproductive health of youth to raise their attitudeenKnowledge,AttitudePreventive practiceSexually Transmitted InfectionThesis