This paper explored the relationship among popularity, self-efficacy and academic achievement of in-school adolescents in Nigeria. The study was a correlational study. The sample of the study was 498 hundred senior secondary school students (female students were 300 while male students were 198). The instruments for data collection were questionnaires titled Adolescents’ Popularity Rating Scale (APRS) and Self-efficacy belief rating scale (SERS). In analyzing the data, mean, standard deviation and linear regression analysis were used in answering the research questions while analysis of variance (ANOVA) was used in testing the three research hypotheses stated at 0.05 level of significance. The results of the study indicate that there is low relationship between popularity and academic achievement of in-school adolescents. The relationship between self-efficacy belief and academic achievement is high and positive. Significant relationship exists between in-school adolescents’ self-efficacy and academic achievement. No significant relationship exists between popularity and academic achievement of in-school adolescents. It is recommended that teachers should always make the students believe that they can achieve academically as this will help them since self-efficacy has positive relationship with academic achievement.
