Young people are increasingly consuming alcohol mixed with energy drinks (AmEDs). As coingestion of these beverages results in greater adverse consequences than from drinking alcohol alone, we need to understand what factors contribute to and deter coingestion. Existing studies in this area have not utilized a theoretically based or empirically validated measure of outcome expectancies for drinking AmEDs. Our study modified Morean, Corbin, and Treat’s (2012) Anticipated Effects of Alcohol Scale to assess the expected effects of drinking AmEDs. We evaluated the factor structure and concurrent validity of the Anticipated Effects of Alcohol Mixed with Energy Drinks (AEAMEDS) among 549 university students, aged 18–25, who had a lifetime history of consuming alcohol (231 had consumed AmEDs in the past 90 days). Exploratory and confirmatory factor analysis supported a 4-factor structure. Consistent with hypotheses, stronger high arousal/positive expectancies and weaker low arousal/negative expectancies were associated with greater AmED use. At the bivariate level, stronger low arousal/positive expectancies were associated with greater quantities of AmED use, but this relationship disappeared when taking into account other outcome expectancies. Moreover, students expected low arousal/positive expectancies to be less intense when consuming AmEDs than alcohol alone, but ratings for all other AmED expectancies were equivalent to consuming alcohol alone. These findings contribute to our knowledge of risk and protective factors for AmED use.