Executive functions (EFs), such as inhibition and cognitive flexibility, are essential for everyday functioning, including regulation of socially appropriate emotional responses. These skills develop during childhood and continue maturing into early adulthood. The current study aimed to investigate the very long-term impact of childhood traumatic brain injury (TBI) on inhibition and cognitive flexibility, and to examine whether global white matter is associated with these abilities. Inhibition, the ability to monitor and control responses, and cognitive flexibility, the ability to switch attention between cognitive demands (Konrad, Gauggel, Manz, & Sch€ oll, 2000), are EF skills particularly vulnerable to childhood TBI (Anderson et al., 2001). Impairments in these domains have been associated with difficulties in everyday functioning, such as regulating socially appropriate emotional and behavioral responses (Beauchamp & Anderson, 2010;Ganesalingam, Yeates, Sanson, & Anderson, 2007;Gioia, Isquith, Guy, & Kenworthy, 2000). SignificanceThis study highlights the enduring impact that childhood traumatic brain injury can exert on survivors throughout late adolescence and into early adulthood. Survivors who sustained traumatic brain injury in childhood did not reflect the typical brain behavior relationship that characterized executive function in adulthood. These findings suggest long-lasting changes in the brain behavior connections following childhood traumatic brain injury, thereby serving as a reminder to refrain from downplaying a head injury sustained in early childhood.