The purpose of the study was to determine the implications of gender streaming on the Kenya Certificate of Secondary Education performance by students in Baringo County, Kenya. The study employed a descriptive survey design with a sample comprising 48 principals and 240 teachers. Data was collected using questionnaires and analysed by use of descriptive and inferential statistics. Based on the study, this paper discusses the factors that influence gender streaming on performance of Kenya Certificate of Secondary Education (KCSE) in Baringo County. The findings indicated that gender streaming influenced students’ performance in KCSE. The findings also revealed that there was no significant relationship between gender streaming and performance across all categories of schools. The findings further revealed that teachers had a positive perception towards gender streaming and students’ academic performance. Based on the findings of the study, it was concluded that much emphasis on girls’ education had improved their performance. It was also concluded that there was no significant relationship in gender streaming and performance in various categories of schools. Majority of the head teachers stated that the performance of girls, compared to boys, in mixed classes was better. Correlations for gender streaming and academic performance indicated a very strong positive relationship between gender streaming and student performance in secondary schools. The study also concluded that teachers had a positive perception towards the influence of gender streaming and students’ academic performance. The study recommended that the government, through the Minsitry of Education, should seek for ways to enhance secondary school administrators to improve students’ performance. Taking the limitations and delimitations of the study, it was suggested that a study on why the boy child lack of empowerment is consistent cause of poor performance among them should be carried out.