How children’s mental health is assessed can depend not only on what is measured, but also who reports it, and which cultural lens is applied. This thesis explores how informant perspective and cultural scoring norms shape the mental health classification of youth with a mobile lifestyle in the Netherlands. The term mobile youth is used here as a broad conceptual category that includes not only Third Culture Kids (TCKs), but also all young individuals whose development is influenced by frequent (inter)national mobility, whether through their own relocations of peers, educators, or community members. Grounded in the Attribution Bias Context (ABC) model (De Los Reyes & Kazdin, 2005), the study examines informant discrepancies and agreements across child, parent, and teacher reports using the Strengths and Difficulties Questionnaire (SDQ). It also evaluates whether (inter)national scoring norms (NL, UK, USA, and 

country/culture-specific) yield different clinical classifications, highlighting how cultural differences can impact who is identified as needing psychological support.