Abstract Background Assessing the early development of children at a population level in educational settings, may be useful for public health and policy decision making. In this study, we evaluated the psychometric properties and the contextual appropriateness of a German language version of the Early Development Instrument (EDI), a survey-based instrument originally developed in Canada, which assesses developmental vulnerability for children in preschool settings. Methods Sixty preschool teachers from six preschool organizations (22% of organizations contacted) in three cities in southwest Germany participated. They administered a German version of the EDI (GEDI) to 225 children (51% of eligible children). We assessed internal consistency, test-retest and interrater reliability. Preschool teachers assisted in determining face-validity by reviewing item coverage and comprehensibility. Exploratory factor analysis (EFA) was used to evaluate convergent validity. Concurrent validity was measured using correlations and agreements (Bland-Altman plots) between GEDI and other validated instrument scores. Additionally, we compared associations between GEDI domain scores and sociodemographic characteristics with similar associations in EDI studies worldwide. Results GEDI domains showed good to excellent internal consistency (0.73 0.99) and moderate to good test-retest and interrater reliability (0.50 to 0.81 and 0.48 to 0.71, respectively [p-value