Writing center literature often notes the stress and anxiety of students as a special concern for peer writing tutors, and tutor training manuals offer advice for tutors on how to manage student writers' anxiety and stress in sessions. Few writing center sources, however, examine the stress/anxiety tutors may experience as a result of their work in the writing center, despite increasing interest in emotions and emotional labor in writing centers. This multi- institutional study examines whether peer writing tutors experience increased stress/anxiety while tutoring. Using a mixed- methods approach combining both surveys and physiological data (salivary cortisol levels controlled against days when they did not tutor), this study investigates the stress/anxiety of 21 tutors across 63 tutoring appointments. The data suggest that peer tutors who enter tutoring sessions in stressed or anxious states are potentially prone to increased stress or anxiety from tutoring. Moreover, they exhibited an inhibited awareness of both student writers' stress and the potential impact of that stress on tutoring sessions. Results suggest that writing centers should increase their focus on tutor well- being, most crucially on emotional labor and its impacts for peer writing tutors.