Background: The Developmental Behaviour Checklist (DBC) is an established, internationally used questionnaire for assessing behavioural and emotional problems among young people with developmental or intellectual disabilities (ID). The present study aims to evaluate the psychometric properties of its German teacher version (DBC-T). Method: The German DBC-T was administered to 397 school staff members who reported twice on 1177 children and adolescents with ID over a period of 7-9 months. Data were analysed within an exploratory structural equation modelling framework. Results: Our results supported the five-factor structure of the DBC-T and found good reliability for all scales. Analyses on the relationship of DBC-T scores with students' age, gender, and adaptive behaviour provided further evidence for the validity of the DBC-T. Conclusions: Our study endorses the notion that the German DBC-T is an important instrument both for research and practice. Limitations and further directions are discussed.