To extend the recent growth of literature on using peer feedback through blogs to enhance students' speaking performance, this study investigated the effects of online peer feedback via blogs on the speaking performance of college students studying English as a Foreign Language (EFL). Participants comprised 45 EFL college students, from two classes English Conversation and English Listening and Speaking, who were required to practice English speaking by recording a series of video clips and giving/receiving peer feedback on their speaking performance. Students also reflected on their experiences at the end of the semester. The collected data included the students' scores on their first and final video clips, their blog entries, and their self-reflection sheets. Based on the differences in scores on their first and final clips, the students were classified into groups who made more progress (MP) and less progress (LP) respectively. After receiving peer feedback through blogs, only the MP group showed significant progress in the development of the content of their videos, including introduction, supporting points and conclusions while both groups showed significant improvement in the delivery area except for vocabulary use and grammar. It was also found that those responding more actively to peers' problematic feedback gained more progress in the revised clips. Several pedagogical implications are also discussed.