Engagement is a core issue in language teaching and learning. Without the students' active involvement in the teaching--learning process, educational objectives could not be achieved. Accordingly, the concept of engagement has been the focus of researchers, practitioners, and policymakers. This research examined the effects of corpus-based instruction on engineering students' engagement in academic writing classes. The participants were 77 randomly selected fourth-year mechanical engineering students. The data were gathered through a self-reflective report and a journal and analyzed through an independent t-test, One-Way ANOVA, and narration techniques. The data showed that students who were instructed via corpus-based instruction improved their behavioral, emotional, and cognitive engagements better than their counterparts; the experimental group enjoyed the activities and actively participated in different academic writing processes. The data also attested that there was a significant statistical difference between the experimental group and the control group engagements. This research implied that EFL teachers should consider genuine and real-life linguistic features and activities when they design academic writing instruction to enhance their engagement during the instruction.