The purpose of this study is to examine the relation of bilateral Friendship, acceptance of peers, self-Concept and social adjustment with the academic achievement of secondary prep school female third graders in Isfahan. The statistical population for this study comprised all the secondary prep school female third graders in Isfahan studying in public school in the academic years of 2001-2002. The sample population size comprised 139 subjects selected using multi-stage randomized cluster and randomized simple fashions. The instruments used in this study were a group-measurement test, Sarasota self-concept scale, social adjustment scale of California personality test. The mean scores for the previous academic year and for the first current semester of each student were employed as indicators of academic achievement. Based on the findings of the study, the correlation of research variables with academic achievement was found to be significant. Moreover, it was specified that a combination of the three variables: self-concept, social adjustment and peer acceptance was capable of explaining a greater rate of changeability of the total mean score of the students for the previous year. The study indicated that a combination of the two variables: peer acceptance and self-concept was capable of explaining a greater rate of changeability for the mean score of the first current semester. Additionally, there was nor significant relation between self-concept and bilateral friendships and between self-concept and peer- acceptance