Fear of negative evaluation, defined as the apprehension that one will be judged unfavorably by others, influences essentially how employees manage their self‐presentation and interpersonal interactions, yet the mechanisms and boundary conditions of this effect remain unexplored. Drawing on Leary and Kowalski's impression management theory and Lazarus and Folkman's Transactional Model of Stress and Coping, this study proposes and tests a moderated mediation model in which self‐confidence mediates the impact of fear of negative evaluation on socially desirable responding, and perceived stress, as a second stage moderator, moderates the strength of this mediating pathway. We collected data from 299 Taiwanese working adults using a three‐wave online survey spaced one week apart to reduce common method bias. Results indicate that higher fear of negative evaluation undermines self‐confidence, which in turn increases socially desirable responding as a defensive strategy; however, this indirect effect is significantly stronger when perceived stress is low and weakens under high stress conditions. These findings contribute to work and organizational psychology by revealing the dual role of individual psychological resources and contextual stressors in shaping self‐presentation behaviors. Practically, our research suggests that interventions aimed at boosting employee self‐confidence and managing workplace stress can foster more authentic communication, improve internal stakeholder engagement, and enhance corporate reputation. By integrating these two theoretical frameworks, this study advances our understanding of the dynamic processes through which evaluative fears translate into behavior and provides actionable insights for practitioners seeking to create healthier, more transparent organizational cultures.