Background: Gender-based violence (GBV) is a common reproductive health problem, especially in developing countries. It is still the first research priority area in Africa that is identified by World Health Organization. The main aim of this study was to identify the prevalence and determinants of Gender Based Violence among Baso high school female students in Debre Berhan town, Ethiopia. Methods: An institutional based cross-sectional study was conducted in Debre Berhan, Ethiopia. A total of 350 female students were selected by stratified sampling technique. A self-administered structured questionnaire was used to collect the data. Each independent variable was fitted separately into bivariate logistic analysis, and Variables with p-values less than 0.25 in bivariable model were fitted into multivariate logistic regression analysis to evaluate the degree of association with gender-based violence. The significance level was obtained with 95% CI and p-value < 0.05. Result: The prevalence of GBV during the lock- down was 36.2% (95% CI 0.3, 0.4), and the lifetime prevalence of GBV was 47.2% (95% CI 0.4, 0.5). The prevalence of life time sexual violence and physical violence were found to be 27.99% (95% CI 0.2, 0.3), and 37.99% (95% CI 0.3, 0.4), respectively. Sexual violence and physical violence during the lockdown were found to be 21.3% and 17.8%, respectively. Respondents educational performance (AOR = 4.5; 95% CI 1.8, 11.3), monthly pocket money received from their parents (AOR = 3; 95% CI 1.6, 5.6), free discussion about reproductive issue (AOR = 2.7; 95% CI 1.4, 5.2), and experience of sexual intercourse (AOR = 13.2; 95% CI 4.8, 36.4) were found to be associated factors of gender based violence. Conclusion and recommendation: Gender Based Violence is still a significant sexual and reproductive health issue in Ethiopia. Governmental and non-governmental organizations should give due attention to this problem. Moreover, further large-scale studies are needed to estimate the national figure of GBV and to identify route causes. Plain Language summary: Gender-based violence (GBV) has been defined as any harmful act that is perpetrated against a person's will and that is based on socially ascribed (gender) differences between males and females. GBV has a myriad of adverse health effects but is vastly underreported. It is the first research priority in Africa. Every form of violence has devastating effects on the school system such as physical and psychological effects, educational damage and societal breakdown. An institution based cross-sectional study was employed among Baso high school female students. There are four governmental high schools in Debre Berhan town and our study was conducted among Baso high school female students from November 2020–December 2020. The single population proportion formula was used to calculate the required sample size, and the final sample size was 350. First, a stratified random sampling method was employed by considering each grade level as a stratum. Then, a simple random sampling method was used to select the study participants. Study participants were asked about their Sociodemographic characteristics, family history, substance use, sexual experiences, physical violence status, sexual violence status and complications. Out of 350 students, 343 were completed questionnaires, with a response rate of 98%. Lifetime prevalence of GBV was 47.2%.Life time sexual violence and physical violence was found to be 27.99%, and 37.99%, respectively. Respondent's educational performance, monthly pocket money received from their parents, free discussion about reproductive issue, and experience of sexual intercourse were found to be determinants of gender based violence. In conclusion; Gender Based Violence is still a significant sexual and reproductive health issue in Ethiopia. Significant amount of female students were victim of GBV in our study area. [ABSTRACT FROM AUTHOR]