This study sought to evaluate the effect of dialogue journal writing on writing performance as well as its different sub-components, namely content, organization, vocabulary, language use, and mechanics (Following Polio, 2013). Participants were 84 EFL intermediate learners who were selected based on their performance on Oxford Quick Placement Test (2004) and divided randomly into experimental and control groups. While the participants in the control group took part in descriptive writing pre and post-tests only, their counterparts in experimental group were asked to write 3 journals a week for about 6 months in the period between the pre- and post-tests. The instructor of the experimental group provided feedback to each journal entry mostly on its content and message to which the participants replied in a dialogic manner. Results of independent sample t-test located a significant difference between the experimental and control group regarding the overall writing performance, as well as the sub-components of content, organization, and vocabulary in the post-test. However, the obtained results did not reveal a significant effect of dialogue journal writing on language use and mechanics of writing performance. The results which promise implications for writing instructors, curriculum developers, and material designers are fully discussed.