Despite a decline in the prevalence of fatal traffic crashes involving adolescent drinking drivers in recent years, underage drinking and driving (DD) and riding with drinking drivers (RWDD) remain serious problems. This article reports the findings of a qualitative study investigating the influence of beliefs and expectancies on adolescents' decisions to participate in DD or RWDD. Forty-four adolescents, who in a previous survey admitted to having been involved in either DD or RWDD, were interviewed in 2000 about their experiences concerning either driving after drinking or getting into a car with a driver who had been drinking. Findings indicate that adolescent DD and RWDD are complex behaviors. Expectancies and control beliefs do not seem to influence the decision, whereas normative beliefs to some extent do. However, findings also indicate that increased enforcement of the laws may be helpful in preventing young people from getting involved in drinking and driving.