The present study investigated the impact of writer-reviewer anonymity in the context of an academic writing course. Data collected for analysis in this study included data from two questionnaires, students' compositions and peer review comments. Embracing a quasi-experimental design, 34 undergraduate EFL students were matched in two homogeneous groups (i.e. anonymous and identified). Each group contained reciprocal dyads (matched with a similar ability peer), and provided either anonymous or identified peer feedback on each other's compositions. The study aimed to examine a) the change, if any, in EFL students' perceptions of peer feedback practice due to anonymity, b) the impact of anonymity, if any, on the amount of written work and the number of peer comments produced, c) the focus of peer comments between anonymous and identified dyads and d) the extent to which anonymity, or lack of it, would encourage/discourage reviewers' criticality in their general evaluative comments and how writers' responded to such evaluative comments. Major results indicated that anonymity positively affects length of written text, time spent in reviewing, number of comments in most language areas and a tendency towards criticality on the side of the reviewers.