This study was an attempt to investigate the impact of Computer Assisted Language Learning (CALL) on Iranian EFL learner's autonomy. To this end, 60 students were selected from a language institute in Tehran. They were then divided into control and experimental groups. A Cambridge ESOL Preliminary Test (PET) was administered to the participants to guarantee their homogeneity. The administration of a proficiency test showed that the two groups were homogeneous in terms of their knowledge of general English. Data was obtained by means of a five-scale Likert questionnaire and analyzed using ANCOVA on SPSS 18.0. The method employed in this research was a quasi-experimental (Nonequivalent Comparison) with pretest and posttest. While both groups were taught by the same instructor and both used the same materials during 20 sessions, English software (BBC Courses) was added to the materials for participants in the experimental group. The findings of this study revealed that the application of CALL had a significant effect on the improvement of students' autonomy. Therefore, CALL appeared to be useful in developing autonomy of EFL learners. The findings of this study carry important implications for foreign language syllabus designers, curriculum planners and language instructors.