Results from a qualitative study with parents about underage drinking are presented. Semistructured interviews (n = 44) were conducted with parents of teens to investigate whether and why parents permit underage drinking. Parents had three primary reasons for allowing underage drinking: deliberate, spontaneous, and harm reduction. Deliberate reasons included passing on knowledge about drinking responsibly and appreciating alcohol. Parents also spontaneously decided to let their teen drink. Some of these spontaneous situations involved feeling pressure from other adults to let their teen drink. Another reason was a desire to reduce potential harm. Parents feared that forbidding underage drinking would harm their relationship with their teen and potentially lead to drunk driving. Prevention efforts aimed at parents should take into account parents' motivations to let teens drink.