This study aims at finding the effect of group work on Iranian EFL learners' writing accuracy. Moreover, the effect of gender on text production has also been investigated. Over a month, sixty Iranian EFL learners were chosen as the participants of this study. They were divided into two groups. The experimental group wrote collaboratively while the control group underwent individual writing tasks. Both groups participated in four essay writing sessions. The participants wrote on the same topics and genre. The results revealed that the students in the collaborative writing group outperformed the students in the control group, hence emphasizing the significant role of collaboration in L2 writing. Regarding gender effect, the data analysis showed the females in the collaborative group outperformed males in the same group proving that gender plays a significant role in Iranian EFL collaborative writing setting. The results have some implications for English writing instructors and learners.