This research study was aimed at examining the potential effect of collaborative corpus-based activities on EFL learners’ writing performance. 90 EFL learners participated in the study and were divided into three groups, namely, two experimental and a control group. All students sat for a writing pretest, followed by practicing writing through using Collins COBULID corpus. Finally, they took part in a writing posttest. The two experimental groups received different treatments and the control group received no treatment. That is, the students in the control group worked with the corpus individually and those in one experimental group were exposed to such treatment and enjoyed collaboration among each other. Students in another experimental group only practiced writing collaboratively while using no corpus. Despite the efficacy of both collaborative writing practice and collaborative corpus-based writing practice in enhancing the students’ writing, results of ANCOVA showed that students in collaborative corpus-based practice group benefited significantly more than the two other groups with regard to the improvement of writing quality. These findings can have implications for teachers, learners, syllabus designers and textbook writers.