This study examined the relationship between teachers' effectiveness and students' academic Performance in Social Studies in Taraba State Nigeria. Specifically, teacher qualification, level of subject-matter knowledge and self-efficacy were the three teacher effectiveness variables correlated with students' academic performance in Taraba State. Four research questions were framed while four corresponding hypotheses were formulated and tested for the study. From a population of 258 Social Studies teachers and 16,158 Junior Secondary School 2 students in public secondary schools, a sample of 89JSS 2Social Studies teachers and 1,780 JSS students was selected using Multi-stage sampling technique. The descriptive survey research design of correlational type was used for this study. Three instruments were utilized for the study two questionnaires and a Checklist. The questionnaires were 25-item Teacher Effectiveness Questionnaire (TEQ) and a 24-item Teacher Self-Efficacy Questionnaire (TSQ). The Check list was tagged Student Performance Checklist (SPC) was used to collect data on students' academic Performance taught by the sampled teachers. The reliabilities of the TEQ and TSQ were obtained using Crombach's Alpha which yielded coefficient alpha values of 0.73 and 0.85 for TEQ and TSQ respectively. Pearson's product Moment Correlation and Linear Regression were used for data analysis. The study found that a significant relationship exist between Social Studies teacher qualification and academic performance of students in secondary schools in Taraba State (r = .474, N= 89, P < .000). There was also a significant but weak relationship between Social Studies teacher pedagogical knowledge of subject matter and academic Performance of students in secondary schools in Taraba State (r = .181, N= 89, P < .002); in addition, Social Studies teacher self-efficacy does not relate significantly to students' academic Performance in Social studies in secondary schools Taraba State (r = .032, N= 89, P = .601). The result also shows that there is a negative relationship between academic performances of students taught by male and female teachers (r = -.003, N= 1780, P = .001). Thus, a correlation index (r = .546) obtained indicates that there is strong positive relationship between effectiveness of teachers and academic performance of students in Social Studies (r = 0.546, p < .05). Therefore, teacher effectiveness accounted for 29.8% (R 2 = 0.298, p < .05) of the total variance in students' academic performance in Social Studies. The study recommends among others that: Government should organize and provide opportunities for training and re-training programmes through seminars, workshops and conference in order to increase teachers' effectiveness; teacher training institutions should inculcate into preservice teachers a deeper professional confidence and competence for maximum teacher effectiveness.