This study examined the effectiveness of the Process Genre Approach (PGA) for teaching writing compared to a conventional teaching approach. Two 11th grade classes from a high school in Indonesia were selected, with one as the experimental group taught using PGA and the other as the control group taught using the conventional approach. Both groups were given pre- and post-tests to assess their writing ability. The results showed that students who received PGA instruction performed significantly better on the post-test compared to the control group, indicating that PGA is more effective at improving writing ability than the conventional approach.