This research investigates the impact of giving and receiving peer feedback on the writing projects of undergraduate EFL students. The study involved six Indonesian undergraduate students enrolled in an article writing course, who participated in peer feedback activities. Using qualitative case study methods, data were collected through interviews, questionnaires, and document analysis to assess the students' experiences. The data was analyzed using an interactive model including data condensation, data display, and conclusion drawing. The study found that peer feedback impacted to both positive and negative. The positive impact was found when the students had the proper knowledge of writing and the negative impact was found when the students lacked the knowledge of writing and the peer feedback activity was not properly monitored by the teacher.