The objective of the study was to establish the impact of Teachers Performance Appraisal(TPA) policy on effectiveness in curriculum evaluation in public secondary schools in Kenya. The study employed a Correlational research design. Additionally, the study used Stratified random sampling technique to select 179 Principals and 179 Deputy Principals. Consequently, the study used questionnaires to collect data from the Principals and Deputy Principals. The study also tested reliability of the instruments for data collection by assessing the scale's internal consistency using Crobanch's alpha, and reliability coefficient of at least 0.7 was achieved. Validity was determined by experts in Educational Administration of Jaramogi Oginga Odinga University of Science and Technology. Quantitative data was analyzed by using descriptive and inferential statistics. The study established that TPA policy had a significant positive influence on curriculum evaluation by teachers (r =.726, p<.05). The study confirmed that TPA: accounted for 52.5% of the variation in curriculum evaluation. The study established TPA to be a significant predictor of curriculum evaluation [F (1, 316) = 351.92, p <.05)]. The study recommends that the Kenyan Teachers Service Commission should enhance the use of reports when making decisions on teachers to be deployed to senior positions and those to be promoted to the next job groups. Such a step would make teachers respect and adhere to the policy guidelines. This is because the study reported that