Abstract: The educational performance of a learning institution is crucial in the attaining educational goals. Thus, the provision of quality education and subsequent high academic performance in school is inevitable for the realization of millennium development goals and the vision 2030. The purpose of this study was to establish the influence of school culture on academic performance in public secondary schools in Trans Nzoia County in Kenya. The study was considered significant and timely because the government, parents and other stakeholders in education spent a lot of resources in education. The study targeted 257 public secondary schools. Using census, all the 257 Directors of Studies from 257 schools were sampled, and 5 Teachers Service Commission Sub-County Director were purposively sampled. A Questionnaire and interview schedule were used for data collection. Data was analysed using frequencies, percentages, weighted averages, simple regression and multi-regression analysis. The study established that school culture significantly influenced academic performances in public secondary schools in Trans Nzoia.