Although often overlooked, sleep disturbances are frequent in ADHD, affecting a sizable proportion of patients. Sleep complaints in patients with ADHD may be due to behavioral factors (e.g., limit-setting disorder), as well as objective alterations, such as delayed sleep-phase disorder, restless legs syndrome, sleep-disordered breathing and the effect of stimulants or associated comorbid disorders. We suggest to systematically screen for sleep disturbances at each visit by means of subjective tools (i.e., questionnaires and sleep diaries) and, when indicated, objective measures (i.e., polysomnography, actigraphy and the multiple sleep latency test). Empirical evidence for the treatment of sleep disturbances associated with ADHD is limited. Besides initial studies on behavioral interventions, the largest and best available evidence demonstrates the effectiveness and good tolerability of melatonin for sleep-onset delay. Further randomized controlled trials of pharmacological and nonpharmacological interventions are needed.