Objective To determine the association of primary caregiver-rated behavioral and metacognitive aspects of executive function (EF) with impaired functioning after adolescent traumatic brain injury (TBI). Design Multicenter cross-sectional study. Setting Outpatient. Participants Primary caregivers and children (N=132) aged 12 to 17 years who sustained a moderate or severe TBI within the past 1 to 6 months. Interventions Not applicable. Main Outcome Measures Primary caregiver ratings of EF, tests of memory and processing speed (PS), and a structured parent interview to assess clinical impairments in behavioral functioning were used. Logistic regression was used to examine the relation of ratings of EF with clinical ratings of impairment in global adolescent functioning and in functioning in the home, school, and community settings after controlling for sex, race, socioeconomic status, injury severity, and performance on the tests of memory and PS. Results Caregiver ratings of poor EF were associated with impairment in both global behavioral functioning (odds ratio [OR]=4.73; 95% confidence interval [CI], 1.54–14.52; P<.01) and community functioning (OR=13.28; 95% CI, 1.94–90.87; P<.01). Conclusions Caregiver ratings of deficits in EF were associated with impaired behavioral functioning after adolescent TBI and were independent of performance on tests of memory and processing speed. Understanding the relation of EF with clinical impairments as manifested in different settings will help hone assessment batteries and focus treatments where they are needed most.