["Sociology of Health & Illness, Volume 43, Issue 4, Page 844-858, May 2021. ", "\nAbstract\nAttention‐deficit/hyperactivity disorder (ADHD) is one of the most controversial childhood psychiatric condition. With the globalisation of its diagnosis and treatment, Taiwan has followed other medically advanced countries in meeting the challenge of medicalising children's problematic behaviours and encountering the resistance discourses on ADHD. To contribute to the extant literature, this study employs the social worlds framework to decipher the relational dynamics amongst these competing discourses on ADHD, namely the mainstream psychiatry, the critiques of overdiagnosis and the antipsychiatric protest, and to suggest the links between these domestic advocacies and the relevant debates abroad. In addition, the concept of boundary‐work is used to analyse the strategies through which these collective actors pursue legitimacy for their respective claims. Based on the existing research of scientific and ethical boundary‐work, this study argues that when it comes to clinical practices fraught with uncertainties, these two seemingly distinct forms of boundary‐work may become mutually supportive in order to act as arbiters of disputes. Despite the disparity of power amongst these social worlds in this case study with seemingly predictable outcomes of the dispute, representing their heterogeneous narratives and the process of discursive struggle helps to destabilise the seemingly naturalised conceptualisation of biomedical ADHD.\n"]