This study explores the effects of stress and burnout on teachers in public secondary schools in Kenya. The research aims to assess the prevalence of stress among teachers, examine its diverse effects on professional performance, and propose implications for educational stakeholders. Utilizing a descriptive survey design, data was gathered through self-constructed questionnaires and interviews. The sample size of the study consisted of 240 teachers and 20 principals from 20 secondary schools. The findings reveal a significant majority of teachers (81.9%) acknowledging the influence of stress and burnout on their performance. This study illustrates the adverse effects reported by teachers, including low output, poor delivery in class, demotivation, lack of concentration, and disorganization. These outcomes underscore the urgent need for targeted interventions and support mechanisms to enhance teacher well-being and the overall quality of education in the region. Implications for policymakers and educational institutions involve prioritizing teacher well-being, implementing organizational support structures, and integrating stress management modules into professional development programs. The study also emphasizes the need for ongoing research to further understand the specific causes and manifestations of stress among teachers in the Kenyan context. Addressing these challenges not only safeguards the well-being of individual educators but also bolsters the resilience and effectiveness of the teaching community, ultimately enhancing educational outcomes for students.