Opioid use disorder (OUD) is a national public health concern. Craving, stress, and exposure to conditioned drug cues are implicated in risk of relapse to opioids. Although impaired sleep has been implicated in risk of relapse to other substances of misuse, little research to date has examined the relationship between sleep and craving in individuals with OUD. The present study examined sleep as a moderator of the relationship between craving and stress in a randomized controlled human laboratory study. Individuals with current OUD (N = 39) completed a 1-night hospital stay to control for factors that may affect craving, stress, and sleep. Sleep was monitored via an actigraphy watch and the Pittsburgh Sleep Quality Index. The next morning, participants were randomized to a 15-min laboratory stress task or a no-stress condition. All participants were then exposed to a 15-min opioid cue paradigm, and craving was measured via self-report. Moderation models were conducted to evaluate whether the sleep indices moderated the relationship between stress condition (independent variable) and craving (dependent variable). Average self-reported nightly sleep duration moderated the relationship between stress condition and craving for participants in the no-stress condition (b = 0.95, p < .05). Specifically, participants in the no-stress condition with lower average nightly sleep duration exhibited significantly greater craving following the opioid cue paradigm. Although preliminary, the findings add to the literature on craving, stress, and sleep among individuals with OUD. Sleep impairment may be an important target of a comprehensive, long-term treatment plan for some patients with OUD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).