This study investigated the effects of process genre-based writing (PGBW) and process writing (PW) approaches on 40 Asian EFL pre-university students’ academic writing performance in a pre-university writing course. The study employed a quasi-experimental research design by dividing the participants in two classes with equal number: 20 students in the process genre-based writing class consisting of 9 males and 11 females, and 20 students in the process writing class comprising 8 males and 12 females. Students’ writing performances were examined using a comparison of their pre- and post-test writing scores. Data analysis revealed that students in both groups showed significant increases in their post-test writing performance after engaging in the PGBW and PW activities; however, learners in the PGBW class obtained higher average mean scores in the post-test writing compared to their peers in the PW class. A significant difference in the overall mean scores for the PGBW and the PW groups after the interventions was at p-value < .05 (t (38) = 3.17, p = .003). These results suggest that the PGBW approach had a greater positive effect on students’ writing performance. Implications of these findings for implementation of the PGBW approach are discussed.