To better characterize pediatric psychopathology after neurological insult, secondary attention deficit hyperactivity disorder (SADHD)-or ADHD that develops after traumatic brain injury (TBI)-and its clinical and neuroimaging correlates were investigated. Outcome data were available for 118 children, ages 5 through 14 at the time of hospitalization following TBI (severe TBI n = 37; mild-moderate TBI n = 57) and orthopedic injury (n = 24). Standardized psychiatric, adaptive functioning, cognitive functioning, family functioning, and family psychiatric history assessments were conducted on all participants. Severity of injury and neuroimaging lesion assessments were conducted on TBI participants only. The diagnosis of SADHD was mutually exclusive with preinjury ADHD, which occurred in 13 of 94 TBI participants and 4 of 24 orthopedic injury participants. SADHD occurred in 13 of 34 eligible participants with severe TBI but resolved in 4 of 13 of these participants. SADHD also occurred in 1 of 8 eligible moderate TBI participants, only in the presence of preinjury ADHD traits and 3 of 39 of eligible mild TBI cases. SADHD occurred in 1 of 20 of eligible participants with orthopedic injury without any brain injury. SADHD was significantly associated with TBI severity recorded by categorical and dimensional measures, intellectual and adaptive functioning deficits, and personality change due to TBI, but not with lesion area or location. These results suggest that SADHD is a clinically important syndrome after severe TBI in children and adolescents.