The objective of this study is to systematically investigate sleep following moderate–severe pediatric traumatic brain injury (TBI). School-aged children with moderate–severe TBI identified via hospital records were invited to participate, along with a school-age sibling. Subjective reports and objective actigraphy correlates of sleep were recorded: Children's Sleep Habits Questionnaire (CSHQ), Sleep Self-Report questionnaire (SSR), and 5-night actigraphy. TBI participants (n = 15) and their siblings (n = 15) participated. Significantly more sleep problems were parent-reported (CSHQ: p = 0.003; d = 1.57), self-reported (SSR: p = 0.003; d = 1.40), and actigraph-recorded in the TBI group (sleep efficiency: p = 0.003; d = 1.23; sleep latency: p = 0.018; d = 0.94). There was no evidence of circadian rhythm disorders, and daytime napping was not prevalent. Moderate–severe pediatric TBI was associated with sleep inefficiency in the form of sleep onset and maintenance problems. This preliminary study indicates that clinicians should be aware of sleep difficulties following pediatric TBI, and their potential associations with cognitive and behavioral problems in a group already at educational and psychosocial risk. (JINS, 2013, 19, 1–6)