Objective: The objective of the study was to establish the high school students’ level of knowledge on HIVAIDS, find out the HIV related attitudes of the students in Vihiga County. Design:The study was a descriptive cross-sectional study. Setting:The study was carried out in Vihiga County Sample. Vihiga County was conveniently sampled. The target population was Students in public secondary schools in Vihiga County who were willing to participate in the study in the schools so mentioned Stratified random sampling technique to be used with regard to the various schools as the strata where proportionately the respondents shall be taken from (n = 45) Analysis. Data was analyzed through descriptive statistics, Independent samples’ T-test and One-way analysis of variance. Main outcome measures:Knowledge and attitude Results. Ninety-eight percent also answered correctly to the statements AIDS is an infective disease caused by a virus‟ and „Any person with HIV can pass it on to someone else during sexual intercourse‟. The majority of the respondents incorrectly believed that a person cannot be infected with HIV without suffering from AIDS (69%) and that a person with HIV cannot look and feel healthy and well (56%).The respondents mostly expressed positive attitudes towards people with HIV/AIDS. On the statements „I think that patients with AIDS have the right to the same quality of care as any other patient‟ and „I would do everything I could to give the best possible care to patients with AIDS‟, 89% answered that they strongly agreed. Bivariate analysis showed that was no significant relationship between knowledge and attitude towards HIV (r (45) =.025, p =.707). This bivariate analysis means that students with positive attitude were not likely to have better knowledge compared to the ones with negative attitude Conclusion: The study established that students had moderate knowledge about HIV/AIDS. The students in general expressed high levels of attitudes towards people living with HIV/AIDS. Addressing stigma in schools should be a continuous process.