Objective: Tolerance to the acute effects of alcohol, i.e., feeling less intoxicated after consuming the same amount of alcohol, has been reported for individuals who regularly consume alcohol. In this study, it was investigated whether such tolerance also exists for experiencing the alcohol hangover. Methods: Data from five studies that assessed hangover frequency and hangover severity were combined (n = 924). Partial correlations were computed between hangover frequency and hangover severity, with age, sex, and weekly alcohol consumption as possible confounders. Results: A significant and positive correlation was found between hangover frequency and hangover severity (r = 0.692, p < 0.001). After correcting for sex, age, and weekly alcohol consumption, the partial correlation remained significant (r = 0.526, p < 0.001). Conclusions: The observed positive association between hangover frequency and hangover severity suggests a reverse tolerance: if hangovers are experienced more frequently, they are more severe.