The purpose of this study is to determine whether there is an influence of teacher performance on the academic achievement of eleventh-grade students in SMK Swasta Nusantara Siborongborong for the 2023/2024 academic year. The research employs quantitative and descriptive methods. The population includes all eleventh-grade students in the Light Vehicle Engineering program at SMK Swasta Nusantara Siborongborong for the 2023/2024 academic year who are Protestant Christians, totaling 60 individuals. The instrument was piloted on 30 respondents, specifically twelfth-grade students for the 2023/2024 academic year at SMK Swasta Nusantara Siborongborong, North Tapanuli Regency. The test yielded 20 valid items as the calculated r-values (ranging from 0.485 to 0.783) exceeded the critical value (r-table = 0.361). This research is a population study. The research instruments included a closed-ended questionnaire for variable X and Midterm Exam scores for variable Y. Data analysis results indicate the following: regression equation, the determination test shows an influence magnitude of 22.18%, and hypothesis testing revealed that the calculated t-value (4.066) is greater than the critical t-value (2.021), leading to the rejection of H0 and acceptance of Ha. The study concludes that there is a positive influence of teacher performance on the academic achievement of eleventh-grade students in the Light Vehicle Engineering program at SMK Swasta Nusantara Siborongborong for the 2023/2024 academic year.