Although the effects of peer-editing techniques have been studied from a variety of perspectives, the results when applied to second- or foreign-language students' writing performance are rarely favorable. The current study looked into the effect of peer-editing on the writing achievement of L2 learners. To achieve the goal, data were collected using a quasi-experimental design. The study's 11th grade participants were divided into two groups using simple random sampling. One of the participant groups was an experimental group that attended L2 writing lessons with peer-editing, while the other group was a control group that was allowed to continue the lesson as usual. Over the course of five weeks, two very different groups received sixteen hours of instruction. A pre- and post-test was given to both groups. The data collected through the writing test was analyzed using the independent sampling t-test and MANOVA. Although there were no statistically significant differences between the two groups in the pre-test results, the post-test results revealed a statistically significant difference at [alpha] = 0.05 level. The findings of this study indicated that, when compared to high school students who received writing instruction in a controlled group, those who learned writing achievements through the peer-editing pedagogical strategy improved their writing achievement. These findings add to our understanding of how peer-editing affects the outcomes of L2 writers.