The current study explores the effect of peer feedback in an English oral presentation class. Much of the previous research interest was given to finding out the degree of agreement between teacher and peer assessments or among students’ assessments, but not the expected advantages of peer assessment itself. Accordingly, 49 Korean EFL university students were recruited, and 25 (i.e., control group) were given only the instructor’s feedback, and the rest 24 (i.e., experimental group) were additionally given peer feedback. The students made five presentations in total, and their midterm and final exam scores between the two groups were compared through independent samples t-tests. The midterm scores were quite similar, but statistically significant differences were observed for the final exam scores. This meant that those who shared peer feedback as a small group during the semester performed much better on the final exam by improving their oral proficiency. Moreover, their responses to a survey questionnaire indicated that they perceived they had greatly improved presentation skills through peer feedback task. In particular, it seemed that small group work and intimacy helped them more to maximize the effect of peer feedback. Pedagogical implications and limitations of this study are further discussed.