This paper studies determinants of drinking behavior and formation of subjective thresholds of acceptable drinking behavior using a sample of students in a major Irish University. We find evidence of strong associations between amounts of alcohol students consume and drinking of their fathers and older siblings. In contrast, we find little evidence of impacts of other non-drinking aspects of family background on students’ drinking. Parental and older sibling drinking appears to affect subjective attitudes of students towards what constitutes problem drinking behavior. We investigated historical origins of drinking behavior including the role of the Church, English cultural influences, the importance of the brewery and distilling industry, and the influence of weather. We find relatively strong influences of the Catholic Church and English colonial settlement patterns on Irish drinking patterns but little influence of Irish weather. Historical licensing restrictions on the number of pubs and off-license establishments also appear to matter.