Peer assessment training has appeared as potential new tools for enhancing Arab English as foreign language (EFL) high school students on writing performance. The purpose of this research was to investigate the effect of using peer assessment training on writing performance among Arab EFL high school students. One hundred and twenty students aged fifteen and sixteen years old participated in this study with an equal number of male and female students. The students were from two Arab high schools in Malaysia. This study employed a quasi-experimental research design. Data was collected using Analytical Marking Scale (Alderson, et al., 1995) to assess student's writing performance in the pretest and posttest. The result of this study shows that there is a significant difference in the writing performances between the experimental and control groups at P < 0.001. The findings suggests that students who have been exposed to peer assessment training write a better draft compared with those students who were only given conventional training in writing an essay, and without the benefit of peer feedback.