The study investigated the influence of Teachers Performance Appraisal (TPA) policy on timeliness in the implementation of the curriculum in Public Secondary Schools in Kenya. The study adopted an Ex post facto design. Additionally, the study population consisted of 5450 teachers, 334 Principals, the TSC-County Director and 334 Deputy Principals of public secondary schools. Stratified random sampling technique was used to select 179 Principals and 179 Deputy Principals. Questionnaires were used to collect data from the Principals and Deputy Principals. Document analysis guide was used to collect data which was not readily obtained through questionnaires. Reliability of the instruments for data collection was tested by assessing the scale’s internal consistency using Crobanch’s alpha and reliability coefficient of at least 0.7 was achieved in all the sub-scales of the questionnaire. Validity was determined by experts in Educational Administration. Quantitative data from questionnaires was analyzed by using inferential statistics, for instance, Linear Regression analysis and Pearson Correlation. The study established that TPA policy had a positive significant influence on; timeliness in curriculum implementation (r=.604, p<.05), curriculum evaluation by teachers (r =.726, p<.05). The TPA was established to be a significant predictor of the timelines in curriculum implementation [F (1, 316) = 181.90, p < .05]. The study recommends that TSC should enforce TPA policy and use it as a tool for promoting and deploying teachers into leadership positions. The study recommends that the Ministry of Education should guide every school to come up with syllabus coverage monitoring tool that can be administered alongside TPA.