Sleep is conceptualized as a restorative factor in people’s ability to exert self-control; however, this possibility has yet to be directly examined. It is likely that sleep replenishes self-control ability by restoring cognitive and motivational factors necessary for enacting self-control. By using daily diary methodology, this study assessed whether changes in self-control, as well as its relevant underlying mechanisms (inhibition, motivation, effort), from evening to the next morning is influenced by the intervening sleep period. To this end, 85 participants were recruited in a two week daily diary study to complete assessments of behavioral (eye blink inhibition) and self-reported self-control (self-control capacity scale) and underlying mechanisms. Sleep was assessed via actigraphy and morning diary entrees. Multilevel structural equation modeling was used to examine if change in self-control and theoretical mechanisms from evening to next morning was predicted by the duration, continuity, or subjective quality of the intervening sleep period. Overnight improvement in eye blink inhibition was predicted by the duration of sleep, which was partially due to co-occurring reductions in the temptation to blink. Additionally, overnight improvement in self-reported self-control capacity was independently predicted by both the duration and subjective quality of sleep, and both of these associations were fully explained by overnight reductions in sleepiness. These findings are the first to link overnight improvements in self-control to sleep, implicating sleep duration as a sleep characteristic that is particularly important for the restoration of self-control. Moreover, temptation, as opposed to motivation and inhibition, emerged as a critical factor explaining the sleep-self-control link.