This paper aims to explore the role of peer Corrective Feedback (CF) in improving written productions by English-as-a- foreign-language (EFL) learners who work together via Wikispaces. It attempted to determine the effect of peer CF on form accuracy in English, such as grammar and lexis. Thirty-four EFL learners at the tertiary level were randomly assigned into the experimental (with peer feedback) or the control (without peer feedback) group; each group was subdivided into small groups of two or three. This resulted in six and seven small groups in the experimental and control groups, respectively. In the experimental group, each learner played a role as an assessor (providing feedback to others), as well as an assessee (receiving feedback from others). Each participant was asked to compose his/her written work and revise it based on the feedback. In the control group, on the other hand, learners neither provided nor received feedback but composed and revised their written work on their own. Data collected from learners’ compositions and post-task interviews were analyzed and reported in this study. Following the completeness of three writing tasks, 10 participants were selected and interviewed individually regarding their perception of collaborative learning in the Computer-Mediated Communication (CMC) environment. Language aspects to be analyzed included lexis (e.g., appropriate use of words), verb tenses (e.g., present and past simple), prepositions (e.g., in, on, and between), nouns, and articles (e.g., a/an). Feedback types consisted of CF, affective, suggestive, and didactic. Frequencies of feedback types and the accuracy of the language aspects were calculated. The results first suggested that accurate items were found more in the experimental group than in the control group. Such results entail that those who worked collaboratively outperformed those who worked non-collaboratively on the accuracy of linguistic aspects. Furthermore, the first type of CF (e.g., corrections directly related to linguistic errors) was found to be the most frequently employed type, whereas affective and didactic were the least used by the experimental group. The results further indicated that most participants perceived that peer CF was helpful in improving the language accuracy, and they demonstrated a favorable attitude toward working with others in the CMC environment. Moreover, some participants stated that when they provided feedback to their peers, they tended to pay attention to linguistic errors in their peers’ work but overlook their own errors (e.g., past simple tense) when writing. Finally, L2 or FL teachers or practitioners are encouraged to employ CMC technologies to train their students to give each other feedback in writing to improve the accuracy of the language and to motivate them to attend to the language system.
 S. C. Tseng, and C. C. Tsai, “On-line peer assessment and the role of the peer feedback: A study of high school computer course,” Computers & Education, vol. 49, pp. 1161-1174, 2007.
 M. M. Nelson, and C. D. Schunn, “The nature of feedback: How different types of peer feedback affect writing performance,” Instructional Science, vol. 37, pp. 375–401, 2009.
 K. Topping, “Peer assessment between students in colleges and universities,” Review of Educational Research, vol. 68, no. 3, pp. 249-276, 1998.
 K. Hyland, and F. Hyland, “Feedback on second language students’ writing,” Language Learning, vol. 39, no. 2, pp. 83-101, 2006.
 Y. Sheen, “Exploring the relationship between characteristics of recasts and learner uptake,” Language Teaching Research, vol. 10, no. 4, pp. 361-392, 2006.
 G. Wigglesworth, and N. Storch, “What role for collaboration in writing and writing feedback,” Journal of Second Language Writing, vol. 21, pp. 364-374, 2012.
 S. L. Thorne, and J. S. Payne, “Evolutionary trajectories, internet-mediated expression, and language education,” CALICO Journal, vol. 22, no. 3, pp. 371-397, 2005.
 Y. Yang, and R. Lyster, “Effects of form-focused practice and feedback on Chinese EFL learners’ acquisition of regular and irregular past tense forms,” Studies in Second Language Acquisition, vol. 32, pp. 235-263, 2010.
 N. Shintani, and R. Ellis, “The comparative effect of direct written corrective feedback and metalinguistic explanation on learners’ explicit and implicit knowledge of the English indefinite article” Journal of Second Language Writing, vol. 22, pp. 286-306, 2013.
 R. Ellis, S. Loewen, and R. Erlam, “Implicit and explicit corrective feedback and the acquisition of L2 grammar,” SSLA, vol. 28, pp. 339-368, 2006.
 T. Heift, “Corrective feedback and learner uptake in CALL,” ReCALL, vol. 16, no. 2, pp. 416-431, 2004.
 R. Schmidt, “Attention, awareness, and individual differences in language learning.” In W. M. Chan, S. Chi, K. N. Cin, J. Istanto, M. Nagami, J. W. Sew, Suthiwan, and I. Walker, in Proc. of CLaSIC, Singapore, December, 2010, pp. 721-737.
 A. Thurston, D. Duran, E. Cunningham, S. Blanch, and K. Topping, “International on-line reciprocal peer tutoring to promote modern language development in primary schools,” Computers & Education, vol. 53, pp. 462-472, 2009.
 J. B. Heaton, Beginning composition through pictures. London: Longman, 1975.
 P. D. Ware, R. O’Dowd, “Peer feedback on language form in telecollaboration,” Language Learning & Technology,” vol. 12, no. 1, pp. 43-63, 2008.