The present study was conducted to explore the effect of dialogic interaction on the writing performance of the Iranian EFL learners. In order to achieve this goal, a quasi-experimental pretest posttest design was utilized. Besides this quasiexperimental design which was responsible for answering the first research question, the researcher used an interview in order to obtain the data for answering the second research question of the present thesis. A total number of 32 participants were selected and assigned to an experimental group (n= 17) and a control group (n=15). They were homogenized using Oxford Placement Test (OPT). They took a pretest and a post test and undergone a nine-session treatment. Since the distribution of the data was normal an independent sample t test was used to compare the mean scores of the groups. The results of the study showed that the dialogic group, the experimental group, outperformed the control group in terms of their achievement in their writing. Moreover, the results of the interview conducted with the learners showed that the attitude of the learners to the dialogic group was positive toward the use of this technique in the writing class.