Abstract: This study examined the impact of strategic plan implementation in sustained focus on instruction and learning in secondary schools in Kenya. The study was informed by Total Quality Management theory is described as a quest for excellence, creating the right attitudes and controls to make prevention of defects possible and optimize customer satisfaction by increased efficiency and effectiveness. The study adopted descriptive survey design since the study investigated possible cause and effect relationship. The location of the study was public secondary schools in Nakuru County, Kenya. The target population was all the 25 public secondary schools, 25 head teachers and 606 teachers. By use of simple random sampling techniques, a sample of 15 schools was sampled, 15 head teacher and 171 teachers, for the study. Questionnaires and interview schedules were used to collect data. The researcher personally visited the sampled schools to collect data. The validity and reliability of the research was determined through the help of the supervisors and vetting by five experts. The results were presented in percentages, graphs and bar charts, frequency tables and pie Charts. The study indicated that strategic planning has positive and significant impacts on instruction and learning. The research outlined conclusions and recommendations to head teachers and all the stakeholders to embark on evaluation of the impact of strategic plan on their school effectiveness.