This study examined the relationship between parental problem drinking (maternal and paternal) and emerging adult problem behaviors (alcohol use, drug use, and antisocial behavior). In addition, the moderating role of parental support (maternal and paternal) was explored. Data were drawn from a nationally representative sample of emerging adults (N = 600; Mage = 20.00, SD = 1.42; 50% women; 62% White). Results from regression analyses of survey data indicated that both maternal problem drinking and maternal support moderated the relationship between paternal problem drinking and emerging adult alcohol use. For drug use, there was a three-way interaction between paternal problem drinking, maternal problem drinking, and maternal support. The relationship between paternal problem drinking and drug use only was significant for those who reported high maternal problem drinking and low maternal support. For antisocial behavior, there were positive relationships between paternal problem drinking and antisocial behavior and between maternal problem drinking and antisocial behavior in contexts of varying levels of parental support. Findings highlight the potential for parental support to both buffer and enhance the adverse influence of parental problem drinking across varied contexts.