Objective: Symptoms of inattention, hyperactivity, and social deficits are observed across clinical populations, including children with Traumatic Brain Injury (TBI) and Attention-Deficit/Hyperactivity Disorder (ADHD). It is unclear whether behavior rating scales distinguish between these clinical groups. Information about the sensitivity and specificity of these measures is beneficial for diagnostic and treatment purposes. It is predicted that ratings of attention, hyperactivity, and social skills will be differentially impacted in these groups. Method: Participants included 346 children with TBI (n = 93), ADHD-Inattentive (n = 163), and ADHD-Combined (n = 90). Children were 11.3 years old and 66.0% male. Children were evaluated in either a day hospital or private practice setting. Diagnoses were established through comprehensive neuropsychological evaluations, which included administration of the mothers' ratings on the Behavior Assessment System for Children, Second Edition (BASC-2). Results: Children with ADHD were in the clinically at risk range for attention problems and received significantly higher ratings than children with TBI, p < .01. Children with ADHD-C received significantly higher ratings of hyperactivity, followed by children with TBI, and then ADHD-I, p < .05. Children with TBI received significantly lower ratings of social skills, p < .001. Conclusion: Findings indicate that the BASC-2 is sensitive to inattention in ADHD, but not in TBI. Prior studies suggest that the focusing component of attention is uniquely impacted in the latter population. Results suggest that further measurements are needed to assess this component. The current study indicates that children with TBI are at greater risk for social deficits than both ADHD presentations and demonstrate increased hyperactivity compared to children with ADHD-I.