This study investigated the relationship between teachers’ job effectiveness and students’ academic performance in public senior secondary schools in Nasarawa State, Nigeria. Two research questions and one null hypothesis guided the study. The population comprised 312 public senior secondary schools and 312 principals, from which a sample of 62 schools and 62 principals was selected using a multistage sampling procedure. Two researcherdeveloped instruments, titled Teachers’ Job Effectiveness Questionnaire (TJEQ) and Students’ Academic Performance Proforma (SAPP), were used for data collection. The instruments were subjected to face and content validation, after which a pilot test was conducted. The reliability index of the TJEQ was established at 0.79 using the split-half method and Pearson Product Moment Correlation Coefficient. Mean scores, standard deviation, and percentages were used to answer the research questions, while multiple regression analysis was employed to test the null hypothesis at the 0.05 level of significance. The findings revealed a high level of teachers’ job effectiveness and a generally good performance in students’ SSCE results from 2014 to 2023, despite observable fluctuations over the ten-year period. The study concluded that teachers’ job effectiveness is a significant predictor of students’ academic performance in public senior secondary schools in Nasarawa State. Consequently, it was recommended, among others, that school principals should provide targeted training opportunities to enhance teachers’ effectiveness in lesson planning and delivery, classroom management, student assessment, and the use of appropriate teaching methods. In addition, school principals, in collaboration with the Nasarawa State Teaching Service Commission, should invest in continuousprofessionaldevelopmentprogrammes and create an enabling environment that supports active teacher participation.