Objective: Around 70% of adolescents with ADHD experience sleep and/or homework problems. Both impairments have been previously associated with neuropsychological deficits but have not been simultaneously examined in adolescents with ADHD and clinical sleep problems. Therefore, this study investigated how sleep problems are associated with homework problems and how parent-rated behavioral indicators of neuropsychological functioning are part of this association in adolescents with ADHD. Method: Parental ratings of homework problems (HPC) and behavioral indicators of neuropsychological functioning (CAMEL) of adolescents with ADHD and comorbid sleep problems (ADHD/sleep; n = 53), adolescents with ADHD only (n = 24), and neurotypical adolescents (NT; n = 53) were collected. Homework problems and behavioral indicators of neuropsychological functioning were compared between the three groups. A path analysis was performed to investigate whether the behavioral indicators of neuropsychological functioning are part of the relation between sleep problems in ADHD and homework problems. Results: We found no differences for either homework problems or behavioral indicators of neuropsychological functioning between the ADHD/sleep and ADHD only groups, except for a small significant difference in arousal regulation, but both ADHD groups showed more homework problems and behavioral indicators of weaker neuropsychological functioning compared to the NT group. Behavioral indicators of weaker neuropsychological functioning were related to the increased homework problems experienced in the ADHD/sleep and ADHD only groups compared to NT. Conclusion: In adolescents with ADHD, sleep problems were not associated with more homework problems by weaker behavioral indicators of neuropsychological functioning. However, regardless of sleep problems, the behavioral indicators of neuropsychological functioning relate to the homework problems in adolescents with ADHD.