Objective: Excess alcohol consumption extorts significant social and economic costs that are increasing despite the presence of mandatory warning labels on packaged alcoholic beverages. We used a novel approach by adding a brief statement based on self-affirmation theory to alcohol warning labels. Method: In two studies (N = 85 and N = 58), we randomized regular wine drinkers recruited from university campuses to complete a wine-pouring task with bottles that had standard labeling or bottles that added a self-affirming implementation intention to the standard labeling. Alcohol consumption, behavioral intention, and self-efficacy were measured premanipulation; message acceptance was measured postmanipulation; and alcohol consumption, behavioral intention, and self-efficacy were measured again at follow-up. Results: In both studies, the self-affirming implementation intention significantly reduced subsequent alcohol consumption (ds = 0.70 and 0.91, respectively). However, message acceptance, behavioral intention, and self-efficacy did not significantly mediate the observed effects. Conclusions: Self-affirming implementation intentions augmented the effect of alcohol warning labels to reduce subsequent alcohol consumption, but—consistent with the broader self-affirmation literature—it was not clear what mediated the effects. Further research is required to examine the effects of self-affirming implementation intentions on other kinds of public health–related labeling.