Based on previous empirical findings, “challenge stressors” (Cavanaugh, Boswell, Roehling, & Bouderau, 2000; Lepine, Podsakoff, & Lepine, 2005), such as the amount and scope of responsibility, can be loosely considered as “good stressors” that are consistently and positively related to job satisfaction and performance. We introduce the role of appraisal to further examine how challenge stressors are connected to performance. Structural equation modelling analyses using an applied sample of 284 employee–supervisor dyads showed that affective commitment to the organization mediated the relationship between both opportunity and threat appraisal and performance (in-role and extra-role). The mediating role of increased psychosomatic distress was supported only for the relationship between threat appraisal and in-role performance. The findings indicate the importance of taking into account the actual appraisal of “challenge stressors”, as it carries implications for performance, and reveals the key role of affective commitment and induced distress mechanisms in this relationship. In conclusion, “challenge stressors” are not always positively related to performance, but only when they are perceived as opportunities.