Traumatic brain injury (TBI) in children and infants is a primary cause of cognitive and behavioral problems that can persist through adulthood. In this study, the long-term behavioral effects of neonatal and juvenile TBI (jTBI) were characterized using mice. At an age of post-natal 7 or 10 days, mice underwent moderate or severe closed skull impact or sham surgery. Behavioral testing was conducted at 6 and 8 months post-injury. Tests administered included the open field activity (general activity levels), zero maze (anxiety), forced swim (depression), rotarod (coordination and balance), and water maze (general/spatial learning). jTBI mice showed elevated activity levels, impaired sensorimotor abilities, impaired spatial learning, and less efficient spatial search strategy use compared with sham animals. These differences were consistent and stable up to 8 months post-injury, suggesting that deficits acquired as the result of a TBI can have long-lasting behavioral impacts.