There is growing research focusing on the sleep problems of children with attention-deficit/hyperactivity disorder (ADHD) in recent years. High incidence of sleep disorders in children with ADHD may be associated with a substantial impact on their quality of life and exacerbation of ADHD symptoms. The core symptoms of ADHD can be effectively treated by various medications, including methylphenidate (MPH), amphetamine, pemoline, and the newly FDA-approved extended-release α2 adrenergic agonists. However, most of them are known to affect patients' sleep because of their pharmacological actions on dopaminergic and/or noradrenergic release in the central nervous system. Previous studies have found increased incidence of insomnia and sleep disturbances in ADHD children treated with CNS (central nervous system) stimulants. In contrast, recent prospective, double-blind, placebo-controlled trials concluded that MPH, by objective polysomnographic or actigraphic measurements, did not cause significant sleep problems in children or adolescents with ADHD. Given the fact that sleep quality and core symptoms of ADHD are highly correlated, it is imperative that we understand the effects of ADHD medications on sleep while prescribing either CNS stimulants or non-CNS stimulants. Here we will concisely review the pharmacological treatments of ADHD, and provide the relevant data discussing their short- and long-term effects on sleep.