this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitude toward the comments given by peers versus teachers in the writing skill. previous studies have mainly focused on other aspects such as the effect of teachers’ comments on students writing and not in comparison to that of the peers. moreover, this study has not been extensively replicated in iran. the teachers assigned participants a number of writing tasks, which were corrected by three groups of feedback providers. the first group of feedback providers were the same proficiency students, the second group, were higher proficiency students, and the last group were teachers. a micro genetic approach was conducted in order to analyze the collected written data gathered by students. besides, the researcher chose some students randomly (because of lack of time) from the participants who carried out the task, to take a part in an interview. also to collect more information from all the participants, a questionnaire was prepared by the researcher and distributed among all the participants as well. the result of analysis revealed that peer comments and teacher comments did not facilitate revision equally. the data revealed that teachers’ comments were both more reliable and influential to the students. results obtained from statistical procedures revealed that different aspects of language were highlighted by different groups. it could be observed that in all groups, grammar is of utmost attention. the final finding of the study, based on the questionnaire and the interview, was about the students attitudes and feelings about teacher’s and peers’ feedback. they preferred to get feedback from their instructor rather than their peers. key words: peer interaction, zone of proximal development (zpd), scaffolding, writing revision