Sexual aggression (SA) is a significant public health problem, with the majority of SA involving alcohol. The present study examined associations between alcohol expectancies for sexual enhancement, event-level alcohol use, and the likelihood of SA perpetration. Young, adult non-problem drinking men participated in a laboratory session and completed a background survey that included measures of alcohol expectancies. Subsequently, men completed 6-week and 3-month follow-up surveys in which they reported their sexual experiences each day during the intervening 6-week period using Timeline Followback procedures. The analytic sample consisted of the 421 men (Mage = 24.66, SD = 2.69) who reported having sex at least once during the follow-up period. Multilevel models showed a significant alcohol expectancies X alcohol use interaction at the between-person level: Controlling for time and alcohol expectancies for aggression, stronger alcohol expectancies for sexual enhancement were associated with greater SA perpetration likelihood among men who consumed high amounts of alcohol before sexual encounters but not among men who consumed low amounts. Alcohol prevention programs should consider addressing men's alcohol expectancies for sexual enhancement to reduce risk for SA perpetration.