This paper estimates the impact of fraternity and sorority membership on a wide array of drinking outcomes among respondents to four Harvard College Alcohol Study surveys from 1993 to 2001. Identification is achieved by including proxies for specific types of unobserved heterogeneity expected to influence the relationship. These include high school and parental drinking behaviors to account for time‐invariant omitted factors and assessed importance of drinking‐related activities and reasons for drinking to control for changes in preferences since starting college. Because self‐selection is quantitatively important, I further hold constant variables plausibly affected by fraternity membership, such as current alcohol use categorization, ranging from abstainer to heavy drinker, and time spent socializing. Even in the fully saturated model, fraternity membership significantly increases drinking intensity, frequency, and recency, as well as the prevalence of many deleterious drinking consequences that potentially carry negative externalities. (JEL I12, I20)