The aim of this study was to examine the relationship between academic performance and the variables of working memory, self-efficacy belief, and test anxiety. The population of this descriptive-correlational study consisted of male students studying at 6th grade elementary school in Tehran. According to Krejcie and Morgan, 373 students were selected, using cluster random sampling. Daneman and Carpenter questionnaire was administered to assess students’ working memory. Pintrich and De Groot learning questionnaire was administered to assess students’ educational self-efficacy belief and test anxiety. In addition, students’ grade point average was used as the indictor of academic performance. In this study, in addition to measures of central tendency and measures of dispersion, Pearson correlation and stepwise regression were used to predict the relationship between academic performance and the independent variables. The result indicated that there were positive and significant relationship between academic performance and the variables of working memory and self-efficacy belief, and negative and significant relationship between academic performance and test anxiety. Regression analysis showed that test anxiety had a greater effect on the dependent variable. Therefore, it is imperative that schools and teachers use appropriate strategies to reduce test anxiety and improve academic performance of students.