This paper investigates the effect of anonymity in online peer review on feedback types (directive, non-directive, higher-order concern, lower-order concern) and students' revisions (processed, partly processed and not processed) in second-language writing. Participants were 114 Dutch second-year university students. They were assigned to two experimental conditions: anonymous and non-anonymous. Results showed that students in the anonymous condition provided significantly more feedback on higher-order concerns and offered significantly different types of feedback than students in the non-anonymous condition. As for revision, overall findings showed that assessees in the anonymous condition did not process more feedback (i.e., the adoption rate) than their non-identified peers, however, assessees in the anonymous condition processed significantly more directive higher-order feedback and scored significantly higher final grades for the writing module than their non-anonymous peers. These results might imply that anonymity could enable learners to provide unreservedly more higher-order concerns feedback type. On the self-same note, the adoption and revision of these higher-order feedback items was instrumental in the improved writing performance of students in the anonymous condition.