In this article, we provide a theoretical framework for understanding how written peer critique can be used successfully to develop authority in students’ writing in the disciplines. We suggest that having students respond to their peers in writing rather than orally and positioning students to write their critiques from a strong knowledge base are key elements in making peer critique valuable to the responder. We describe the use of written peer critique in a second-year communications studies course and discuss examples from students’ critiques of summaries written by their peers. A strong authorial presence is revealed in three main areas: students’ evaluative comments related to disciplinary content; students’ evaluative comments on their peers’ handling of the summary genre; and students’ personal authority derived from their experience as readers.