Study Objectives: Alcohol abuse is a significant public health problem, particularly in populations in which sleep deprivation is common as such as shift workers and aged individuals. Although research demonstrates the effect of alcohol on sleep, little is known about the role of sleep in alcohol sensitivity and toxicity. We investigated sleep as a factor modulating alcohol toxicity using Drosophila melanogaster, a model system ideal for studies of sleep, alcohol and aging. Methods: Following 24 hours of sleep deprivation using mechanical stimulation, Drosophila were exposed to binge-like alcohol exposures. Behavioral sensitivity, tolerance, and mortality were assessed. The effects of chronic sleep deprivation on alcohol toxicity were investigated using a short sleep mutant insomniac. Pharmacological induction of sleep for prior to alcohol exposure was accomplished using a GABAA-receptor agonist, 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol (THIP) to determine if increased sleep mitigated the effects of alcohol toxicity on middle-aged flies and flies with environmentally disrupted circadian clocks mimicking groups more vulnerable to the effects of alcohol. Results: Acute sleep deprivation increased alcohol-induced mortality following alcohol exposure. However, sleep deprivation had no effect on alcohol absorbance or clearance. Sleep deprivation also abolished functional tolerance measured 24 hours after the initial alcohol exposure, although tolerance at 4 h was observed. Pharmacologically increasing sleep prior to alcohol exposure decreased alcohol-induced mortality. Conclusions: Sleep quantity prior to alcohol exposure affects alcohol toxicity with decreased sleep increasing alcohol toxicity and dampened 24-hour alcohol tolerance. In contrast, increased sleep mitigated alcohol-induced mortality even in vulnerable groups such as aging flies and those with circadian dysfunction.