Recent studies have highlighted the significance of learners' engagement with written corrective feedback (WCF). However, comparative studies exploring graduate students' engagement (i.e., cognitive, affective, and behavioral) with peers and teachers' feedback in an L2 writing course is scarce. Hence, this multiple case study, using various sources such as a semi-structured interview, a narrative inquiry sheet, a peer feedback sheet, and students' writing tasks, explored Iranian EFL graduate students' engagement with peer- and teacher feedback. The findings revealed that all of the learners were engaged with the WCF they received from both their peers and instructor. However, the intensity of each dimension of engagement with peer and teacher WCF was different. Specifically, as for peer-feedback engagement, we found that behavioral engagement was the most frequent engagement type. The second most frequent was cognitive engagement and the least common was affective engagement. As for teachers' feedback engagement, the findings revealed that cognitive engagement was the most frequent engagement type. The second most frequent was affective engagement, and the least common engagement type was behavioral engagement. Implications and recommendations with regards to learners' engagement with peer and teacher written feedback are discussed in the light of the findings.