This study investigates the effect of Dicto-gloss as a cooperative learning technique on the perceived self-efficacy of Iranian EFL learners in writing. There were 46 Persian speaking EFL learners participated in this study. Out of 46, 23 participants were taken as the experimental group and the other 23 as the control group. They were heterogeneous due to the cooperative nature of the study. As the first phase of data collection, a self-efficacy in writing questionnaire developed by Yavuz-Erkan (2004) was administered to both groups as a pretest in order to evaluate the degree of their self-efficacy in writing. The experimental group was exposed to the Dicto-gloss technique of cooperative learning, while the control group was exposed to the traditional method of writing instruction in TEFL writing classes. After 13 sessions of treatment, the self-efficacy in writing questionnaire was reapplied to both groups as the post test. The participants' scores in the two groups were calculated and compared. The results revealed a difference between the two groups, indicating the effects of THE dicto-gloss technique of cooperative learning on self-efficacy in the writing of EFL learners.