Objective: Pediatric traumatic brain injury (TBI) is associated with a variety of cognitive, academic, and social/emotional difficulties. Some difficulties emerge over time as a function of development following neurological insult. However, there is a paucity of longitudinal research examining factors associated with functional outcomes. The present study examined the relationships between social, emotional, and behavioral factors and global cognitive functioning at five years post-injury. Method: 11 subjects who experienced moderate-to-severe pediatric TBI were evaluated at 12 and 60 months post-injury. Longitudinal change in IQ score was calculated and correlated with parent ratings of behavioral, social, and emotional functioning at 60 months post-TBI using the Behavior Assessment System for Children, Second Edition (BASC-2). Parent ratings of executive functioning from the Behavior Rating Inventory of Executive Function (BRIEF) also were examined. Results: At 60 months post-injury, change in IQ from the 12-month post-injury time point was significantly correlated with parent-reported symptoms of depression (r = −.701, p = .016), somatization (r = −.619, p = .042), and withdrawal (r = −.612, p = .045) but not with any other BASC-2 factors at 60 months post-TBI. IQ change also was associated with emotional control as measured by the BRIEF at 60 months (r = −.718, p = .013) but not with other aspects of parent-reported executive functioning. Conclusion: Declines in IQ at five years post-TBI were associated with increased symptoms of depression, somatization, and withdrawal and greater problems with emotional control. Findings highlight the long-term cognitive and social/emotional impact of pediatric TBI, and implications for intervention are discussed. Limitations of this small pilot study are acknowledged, and directions for future research are presented.