This study draws on the family systems concepts of triangulation and wholism to investigate how interparental conflict may affect adolescents' psychological adjustment. An ethnically and socioeconomically diverse sample (N = 388) of 14- to 18-year-olds completed measures of interparental conflict, family relationships, internalizing problems, and externalizing problems. We found that triangulation into parental disagreements mediated the association between parental conflict and both internalizing and externalizing problems. Adolescents exposed to more frequent, intense, and poorly resolved conflict were more likely to feel triangulated, but this association was moderated by the nature of the alliances they had with their parents. Specifically, at low levels of interparental conflict, adolescents who had substantially stronger alliances with one parent than the other reported greater triangulation than those with more balanced alliances. At high levels of conflict, these groups reported similar degrees of triangulation. We also found that supportive parent-child relationships reduced adolescents' appraisals of threat and self-blame for interparental conflict, while more empathic relationships with siblings increased these appraisals. Finally, close relationships with fathers acted as a protective factor that reduced symptoms of maladjustment.