Based on 9 months of ethnographic fieldwork in a U.S. mental health clinic focused on the treatment of preschool-aged children who exhibited extremely disruptive behavior, this article examines the contradictions clinicians faced when trying to identify and attribute "intentionality" to very young children. Disruptive, aggressive behavior is one of the central symptoms involved in a wide-range of childhood psychopathology and the number one reason young children are referred to mental health clinics in the United States. In the clinic where I conducted my research, clinicians were especially interested in diagnosing these children with oppositional defiant disorder (ODD), in order to identify those at risk for more serious mental illness later in the lifecourse. In this article, I look at the different strategies clinicians used in interpreting whether aggressive, defiant behavior was a part of the child's "self," a biologically driven symptom of a disease, or a legitimate reaction to problematic social environments. I argue that conceptualizing intentionality as a developmental, interpersonal process may help to make sense of the multiple discourses and practices clinicians used to try to reconcile the contradictions inherent in diagnosing ODD.