Objective. To introduce the progress in genetic studies in attention-deficit hyperactivity disorder with particular emphasis on findings in Han Chinese. Methods. The literature review included peer-reviewed articles on Medline, the China National Knowledge Infrastructure database, and references since 1980 were hand-picked. Results. Several candidate genes have a substantial role in the aetiology of attention-deficit hyperactivity disorder. Possible confounding influences include: population admixture, environment and its interactions with genetic factors, diagnostic criteria, ethnicity, and genotype. Conclusions. Diversity of the relationships of genes with attention-deficit hyperactivity disorder exists across different ethnic groups. Therefore, findings in western countries may not apply to other ethnic groups, including the Han Chinese population.