This study aimed at comparing the effects of reflective learning portfolio (RLP) and dialogue journal writing (DJW) on the Iranian EFL learners' grammatical accuracy in writing as well as their overall writing performance. 60 Iranian EFL learners between the ages of 17 to 30 who were studying at general English courses were selected based on their performance on the Nelson English Language Test. They were assigned randomly into two experimental groups: DJW and RLP. Each group received 14-sessions of treatment. Two samples of Task 2 of General Module of IELTS were used for the pretests and posttests. Each essay was scored independently by three raters. The final score consisted of the average score of the three raters.The findings revealed that the gains in the RLP group's grammatical accuracy and overall writing performance were significantly better than that of the DJW group. This could have been due to the influence of reflection with support of a mentor or collaborator as well as the efficacy of intentional learning over incidental one and explicit learning over implicit one. The results have some main implications for syllabus designers, material developers, and language teachers.