This study explored the mediating role of interest in enhancing academic performance and selfesteem of Basic II students in Benue State, Nigeria. Two research questions and two hypotheses guided the study. The study adopted a cross-sectional survey. The population for the study was upper basic II Students. The population of the study consisted of 15,623 Upper Basic II students from 162 UBE schools. A total of 390 Upper Basic II students in 36 schools were sampled using multi-stage sampling technique. Three validated instruments were used for data collection namely; Basic Science Performance Test (BSPT), Students’ Interest in Basic Science Questionnaire (SIBSQ) and Basic Science Students’ Self-Esteem Questionnaire (BSSSQ. The reliability coefficients of 0.82, 0.70, and 0.90 were obtained for the SIBSQ, BSSSQ using Cronbach’s Alpha and BSPT using Kuder-Richardson Formula 20 (KR-20) respectively. Basic Science teachers from the sampled schools were trained as research assistants to administer the instruments directly.

Mean scores and standard deviations were used to answer the research questions. T-test was used to test the null hypotheses at 0.05 level of significance. The findings reveal that there was a significant difference in the mean self-esteem ratings in Basic Science between students with high, and low interest (t= 1.852, p=0.045 < 0.05). There was a significant difference in the mean performance scores in Basic Science between students with high interest and those with low interest. (t = 2.842, p=0.005 < 0.05). Therefore, it was concluded that students with high interest and those with low interest recorded a significant difference in their mean performance scores particularly in Basic Science. It was recommended that, Basic Science teachers should endeavor to create opportunities for learners to engage in learning Basic Science during planning; delivering and assessment of their lessons to enable students develop interest which could lead to high self-esteem and also which may tend to improve students’ performance in Basic Science.