AbstractDrawing from social exchange theory, this study investigates how and when supervisor evasive knowledge hiding might lead to lower job performance by employees. The hypotheses were tested with three‐round survey data, collected among employees and peers in various industries. Employees' perceptions that their supervisor engages in deceptive knowledge hiding undermine their own performance‐enhancing efforts because they develop career plateau beliefs; this explanatory role is particularly salient among employees exposed to despotic leadership. This study pinpoints a notable risk for employees who feel upset when they believe a despotic supervisor is intentionally concealing knowledge: They grow disappointed with their career situation, which prompts them to adopt complacent behavioral responses that likely render it even more challenging to access valuable supervisor knowledge.