This paper investigates the relationship between self-efficacy and Academic Achievement among 300 girl students in second year of high schooling. The students are majoring in math-physics and in human sciences in the 6th educational district of Tehran. The research instrument used was MJSES Scale. This scale contains three components: talent, context, and effort. The mean score obtained in verbal (literature, Persian syntax, and conjugation) and mathematics (geometry, math, and statistics) tests was also used as a measure of Academic Achievement.The results showed that in both groups, the Academic self-efficacy could predict Academic Achievement. The results of step-wise regression indicate that the Effort Component is a more powerful predictor of the Academic Achievement than the Aptitude and Context. Furthermore, analysis of variance on all variables: Academic self-efficacy, effort, aptitude and context components, and Academic Achievement showed that the two groups are significantly different in Academic self-efficacy, Academic Achievement and aptitude component, but no significant difference in effort and context components were observed. These results imply that if the Academic self efficacy of a student increases and if the context of school and home provides the best for the student, their Academic Achievement, and the probability of selecting the math-physics field will also increase.