A study published recently in Rehabilitation Psychology examined the effects of age at injury on the persistence of behavior problems and social skill deficits in young children with complicated mild to severe traumatic brain injury (TBI). A concurrent cohort/prospective research design was used with repeated assessments of children with TBI (n = 82) or Orthopedic Injury (OI) (n = 114). Parents completed the Child Behavior Checklist, the Behavior Rating Inventory of Executive Functions, and the Preschool and Kindergarten Behavior Scales or the Home and Community Social and Behavior Scales shortly after injury to assess preinjury functioning, and at an extended follow-up an average of 38 months postinjury. Generalized linear modeling was used to examine the relationship of age at injury to the maintenance of behavior problems, and logistic regression was used to examine the persistence of clinically significant behavior problems. Results: At the extended follow-up, severe TBI was associated with significantly greater anxiety problems relative to the Group OI. With increasing time since injury, children who sustained a severe TBI at an earlier age had significantly higher levels of parent-reported symptoms of ADHD and anxiety than children who were older at injury. Conclusions: Findings suggest that longer-term treatment for behavior problems may be needed after severe TBI, particularly for those injured at an earlier age.