Attention Deficit Hyperactivity Disorder (ADHD) is one of the most expensive mental disorders, costing U.S. citizens $77 billion every year (Reinberg, 2004). Although ADHD effects between 3-7% of U.S. children (American Psychiatric Association [APA], 2000), there are many misconceptions about the disorder and concerns have been raised regarding appropriate diagnosis and treatment in children, adolescents, and adults. In addition to these concerns, several authors have noted that there is a lack of research regarding ethnicity and ADHD. The limited research that has been done is confusing with some studies indicating that there is no difference in rates of ADHD diagnoses (Nigg, 2001) and other studies indicating that African American children are placed in behaviorally disordered classrooms at higher rates (Maddox & Wilson, 2004). Reid, Casat, Norton, Anastopoulus, and Temple (2001) found that teachers were more likely to exhibit a bias in their rating scales if their students were African American. The purpose of this paper is to review the literature on ADHD, with a particular focus on the research of ethnicity and ADHD.