This study aimed to investigate the effect of teaching discourse markers (DMs) on Iranian intermediate EFL learners’ speaking achievement. In the first step, 60 homogeneous intermediate students out of 110 were chosen from a private English language institute and randomly divided into two equal groups, namely an experimental group and a control group. Then they were pretested through a researcher-made speaking test. During the treatment, the experimental group was taught DMs by conversations. Then, they found the DMs in transcriptions of conversations. Also, the researcher used a researcher-made booklet containing the instructional materials related to DMs to be taught to the learners. On the other hand, there was not any direct instruction to DMs to the students in the control group. They only narrated the assigned storybook, and performed conversations by role play. These posters were used based on the related topics of the learner’s textbooks. After the treatment which took 12 sessions, the researcher administered the modified version of the mentioned pre-test as the post-test to find out the effect of the treatment on the participants’ speaking achievement. When the data were collected, one-way ANCOVA was run to analyze them. The results showed that there was no significant difference between experimental and control group in the post-test. Indeed, the findings indicated that teaching discourse markers (DMs) did not have any effect on Iranian intermediate EFL learners’ speaking achievement.
