Despite extensive ties between sleep disruption, anger, and aggression, it is unclear whether sleep loss plays a causal role in shaping anger. On one hand, negative affect and distress frequently follow curtailed sleep, suggesting increased anger responses. On the other hand, fatigue and withdrawal also follow, potentially muting anger. To examine these competing possibilities, 142 community residents were randomly assigned to either maintain or restrict their sleep over 2 days. Before and after, these participants rated their anger and affect throughout a product-rating task alongside aversive noise. Sleep restriction universally intensified anger, reversing adaptation trends in which anger diminished with repeated exposure to noise. Negative affect followed similar patterns, and subjective sleepiness mediated most of the experimental effects on anger. These findings highlight important consequences of everyday sleep loss on anger and implicate sleepiness in dysregulation of anger and hedonic adaptation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).