Objective: To examine differences in risk factors and comorbid conditions for oppositional defiant disorder (ODD) symptom groups in a sample of 248 elementary schoolboys (ages 6-10) recruited from 1994 to 1996. Method: The boys and their mothers received multiple assessments of cognitive, behavioral, academic, and family functioning, including a clinic-based evaluation in Stony Brook, NY. ODD was defined using four different strategies for aggregating data from mother and teacher reports of DSM-IV symptoms. Results: Source-specific ODD symptom groups had better internal validity and were more differentiated than groups defined using the other strategies. The mother-defined ODD symptom group (ODD/M) had higher levels of maternal detachment than the teacher-defined symptom group (ODD/T), and the ODD/T group had more social problems than the ODD/M group. The classification agreement group (ODD/M + T) evidenced higher levels of sensation-seeking, maternal control, and comorbid symptoms than the ODD/M and ODD/T groups. Controlling for co-occurring attention-deficit/hyperactivity disorder and conduct disorder symptoms altered some of the relationships among ODD, comorbid symptoms, and psychosocial correlates. Conclusions: Patterns of co-occurring psychiatric symptoms and psychosocial correlates of ODD symptom groups varied depending on the rater(s) used to determine group membership. Results support continued research into source specificity for conceptualizing ODD. (Contains 3 tables.)