This study attempts to test the effectiveness of a feedback model which combines teacher and peer feedback systematically on improving students' writing ability in the context of a multiple draft writing course. 57 Turkish EFL students participated in the study which lasted for a 15-week semester. The experimental and control groups were provided different feedback treatments and then statistically compared in terms of the revisions they made in their essay drafts and their writing improvement. A total of 1197 essay drafts, were coded and compared for three types of revisions: content, organization and form. In order to collect data on students' attitudes towards writing and feedback, students were given a questionnaire and asked to write reflections about their writing process. Calismanin sonuclari gostermistir ki, geleneksel ogretmen donutu modeli genel anlamda daha fazla duzeltme yapilmasini saglarken, iki farkli donut uygulamasi duzeltme kalitesi ve yazma becerisi gelismesinde istatistiksel acidan farkli sonuclar ortaya cikarmamistir. The results of the study revealed that while the traditional teacher feedback model created more revisions, the two different feedback models did not create statistically meaningful differences in terms of number of revisions and writing quality. However, the combined peer-teacher feedback model was found to be more successful in creating more positive attitudes towards peer feedback and self-revision. In terms of attitudes towards the difficulty of writing activity, on the other hand, important differences were not detected. Based on these results, suggestions have been made about the design and application of feedback activities in the writing class.