An approach called Student Teams Achievement Division (STAD) has been developed based on
Cooperative Learning (CL) tenets. STAD emphasizes having team goals and success dependent on the learning
of all group members. The purpose of the present study was to investigate the effects of STAD on the English
achievement of Iranian third grade junior high school students. 60 third grade junior high school students
(consisting of 2 classes, experimental and control) were chosen. Before the intervention took place, they had
studied 2 lessons (1 & 2) of third grade junior high school book (English Ш) in one and a half months. For a
period of 2 months, in the experimental class the teacher with the help of the researcher implemented STAD
technique, and in the control group the teacher used the same traditional method. Two lessons (3 & 4) were
taught during these 2 months. The materials of this study consisted of 2 teacher-made English achievement
tests, and a questionnaire measuring their learning style preferences. The data was analyzed using paired and
independent t tests. The results showed that the difference between the 2 classes was significant, and the
experimental group was superior to the control group in terms of English achievement.