Although peer review has been shown to be beneficial in many writing classrooms, the benefits of peer review to the reviewer, or the student giving feedback, has not been thoroughly investigated in second-language writing research. The purpose of this study is to determine which is more beneficial to improving student writing: giving or receiving peer feedback. The study was conducted at an intensive English institute with ninety-one students in nine writing classes at two proficiency levels. The "givers" reviewed anonymous papers but received no peer feedback over the course of the semester, while the "receivers" received feedback but did not review other students' writing. An analysis in the gains in writing ability measured from writing samples collected at the beginning and end of the semester indicated that the givers, who focused solely on reviewing peers' writing, made more significant gains in their own writing over the course of the semester than did the receivers, who focused solely on how to use peer feedback. Results also indicated that givers at the lower proficiency level made more gains than those at higher proficiency levels and that slightly more gains were observed on global than local aspects of writing. (Contains 1 figure and 2 tables.)