Background: Children with ADHD are reported to have sleep problems and neuropsychological deficits, but studies examining a potential association between the two are scarce and the use of varying methodology can complicate conclusions. Participants: A clinical sample of 59 medication-naïve children with ADHD between the ages of 6 and 14 years (71% male). Methods: Children underwent polysomnography and multiple sleep latency test, and parent rated sleep habits on the Children’s Sleep Habits Questionnaire. Children also completed an extensive neuropsychological battery of executive function and delay aversion tasks, and parents and teachers rated executive function behavior on the Behavior Rating Inventory of Executive Function. Linear regression analyses were conducted with each of the neuropsychological outcomes included as the outcome variable and the sleep parameters as the predictor variables. Results: The correlations between sleep and neuropsychological outcomes were generally modest, but some sleep parameters (primarily sleep stages and sleep latencies) were associated with objectively and subjectively measured executive function and delay aversion. Conclusions: Using objective and subjective gold standard assessment procedures this study supports a (modest) association between sleep and neuropsychological function in children with ADHD.