Students' academic achievement is a joint outcome of students' trait, task, and instruction(treatment). But the purpose of the present study is to highlight the importance of the individual student variables in the academic achievement situation. Students' locus of control and need variables are investigated. Locus of control is the generalized expectancy for internal or external control of reinforcement which has been previously found to affect students' academic achievement. Need is the analytic object of motivational process and is thought to be one of the essential inner conditions for learning activity. Therefore, it is predicted that locus of control and need affect academic achievement. Researchers have been paying more attention to variables such as intelligence or instruction while neglecting need variables. Subjects were 604 students who were selected from second graders in junior high and in senior high schools. The I-E Locus of Control Scale for Students(the Nowicki & strickland’s scale was translated by Jung, Eun-Joo and Son, Jin-Hoon) and Diagnostic Need Inventory (by Whang, Jung-Kyu) were used. Students were classified into high (30%), middle(40% ), and low( 30% ) achieving groups based on school achievement scores. There was a significant positive correlation between internal locus of control and academic achievement for junior high school students. Academic achievement was positively related to the achievement need as well as to the exhibition need for junior high school students and for female senior high school students. Need scores(n Achievement, n Abasement, n Aggression, n Autonomy) showed significant differences for the internal and the external control groups.