The present study explores the relationship between self-esteem, self-efficacy, and academic achievement among Iranian graduate students majoring in English Language Teaching (ELT) by presenting a model of the interrelationship among these three constructs. To this end, 229 students, male (N=80) and female (N=149), were selected from among different universities of Khorasan Razavi Province, Iran. AMOS software, Schwarzer, and Jerusalem's self-efficacy questionnaire were utilised to conduct the study and Rosenberg's self-esteem questionnaire. Also, to assess the participants' academic achievement, their Grade Point Average (GPA) was used as a criterion measure based on their self-report evaluation. The results of the Pearson correlation indicated that there were significant positive relationships between self-efficacy and self-esteem (r=0.641, p<0.05), self-efficacy and academic achievement (r=0.609, p<0.05), and self-esteem and academic achievement (r=0.519, p<0.05). The goodness of fit indices revealed that all the fit indices lie within the acceptable fit thresholds. Results of the model showed that both self-efficacy ([beta]= 0.44, p<0.05) and self-esteem ([beta]= 0.22, p<0.05) were significant positive predictors of students' achievement. Therefore, self-efficacy was a better predictor of GPA. The model also demonstrated that self-efficacy positively and significantly ([beta]= 0.57, p<0.05). The findings of the study might have some pedagogical implications for language teaching and learning.