Objective: This study examined nighttime media use in relation to sleep problems and anxiety/depression symptoms in adolescents with attention-deficit/hyperactivity disorder (ADHD). Methods: Participants were 81 adolescents (69% male) ages 13-17 with ADHD. Adolescents completed measures assessing pubertal development, nighttime media use, circadian preference, and daytime sleepiness. Both adolescents and parents completed measures of sleep duration, sleep problems, and internalizing symptoms. Results: When summing across media uses (eg, social networking, playing video games, watching television), the average nighttime media use (after 9:00PM) was 5.31 h. Overall, 63% of adolescents reported obtaining less than 8 h of sleep on school nights, and this percentage rose to 77% for parent-reported sleep duration. Moreover, adolescents obtaining less sleep than recommended had more nighttime media use than those obtaining >= 8 h of nightly sleep. Controlling for age, sex, pubertal development, stimulant medication use, and ADHD symptom severity; nighttime media use was associated with shorter sleep duration and increased sleep problems across both adolescent and parent report. Media use was also associated with greater adolescent-reported anxiety and depression, and marginally associated with eveningness circadian preference and greater daytime sleepiness. In considering specific anxiety dimensions, media use was associated with greater adolescent-reported panic symptoms and parent-reported generalized anxiety disorder symptoms. Conclusions: Our findings suggest that nighttime media use may contribute to sleep problems and co-morbid internalizing symptoms in adolescents with ADHD, although additional studies are needed to determine causality, potential bidirectional associations, and underlying mechanisms such as using media to (mis)manage negative emotions. Media use is important to assess and monitor and may be a significant intervention target when addressing sleep and internalizing problems, and possible underlying cognitive-emotional processes in adolescents with ADHD. (C) 2018 Elsevier B.V. All rights reserved.