There is evidence that daily negative events at work enhance fatigue. In contrast, positive events may trigger processes that increase, but also processes that decrease, energetic resources. Accordingly, results regarding a main effect of positive events on fatigue have been mixed. However, a clearer pattern between positive events and fatigue can be expected under adverse circumstances (i.e., accumulation of negative events, high chronic stressors). Positive events may facilitate coping and accelerate recovery processes and, thus, reduce resource drain due to daily negative events and chronic stressors. Predicting fatigue in a diary study with 76 employees, we investigated interactions between daily positive events and (a) daily negative events and (b) chronic social stressors. Multilevel modeling revealed that negative but not positive events were associated with increased end-of-work fatigue. However, positive events interacted with negative events and with chronic social stressors. As expected, positive events were negatively associated with fatigue only on days with many negative events, but not so on days with few negative events. Analogously, positive events were negatively associated with fatigue only among employees with high, compared with low, chronic social stressors. We conclude that the beneficial short-term effects of positive events on energetic resources are largely confined to adverse circumstances.