Objective: Relatively little is known about the effects of low-dose alcohol effects on attentional performance in adolescents. In the present study, we examined these effects compared to those in adults. Method: 44 healthy subjects (21 adolescents and 23 adults) received either an alcoholic cocktail (average blood alcohol concentration: 0.054 %) or a placebo drink (randomized placebo-controlled). Before and after consuming the drink, participants completed tests on Alertness, Working Memory, Flexibility and Divided Attention. Results: Significant effects were found for the subtest Flexibility, which showed less improvement in the adolescents with alcohol compared to the non-alcohol condition and adults. Furthermore, an age-independent alcohol-induced impairment of the subtest Working Memory was observed. Conclusions: These findings point to a particular vulnerability for alcohol effects in adolescents regarding cognitive flexibility.