There is a well-established correlation between sleep disturbances and attention deficit hyperactivity disorder (ADHD). A large number of pediatric patients diagnosed with ADHD have sleep problems, while patients with sleep disturbances often display behavioral patterns that resemble some features of ADHD. Despite these observations, the relationship between sleep problems and ADHD is not yet fully understood. It is often difficult to pinpoint which of the disorders is the primary and which a byproduct of the other. A complicating factor is that stimulant medication such as methylphenidate, a drug of choice for ADHD, may adversely affect sleep quality in ADHD patients. However, there have also been reports that it may actually improve sleep quality. This review examines the latest trends in the contemporary literature on this clinical dilemma.