Prior research suggests that sleep is associated with increased subjective stress and aggression, but important questions remain about the typical magnitude of these relationships, as well as their potential moderators. We therefore conducted the first meta-analysis of this literature. Across 340 associational and experimental studies, significant associations were identified between sleep with both subjective stress (r =.307, p <.001) and aggression (r =.258, p <.001) in individuals from the general population, as well as between sleep with subjective stress (r =.425, p <.001) in individuals with sleep disorders. Experimental sleep restriction also led to increased subjective stress (g = 0.403, p =.017) and aggression (g = 0.330, p =.042). These findings suggest that poorer sleep is associated with - and leads to - heightened levels of subjective stress and aggression. These findings, and their implications, are discussed in relation to neurobiological literature, which highlights the complex interplay between metabolic activity in the brain, hormonal changes, and behavior.