Many countries rely on statements issued by professional associations to delimit the scope of school psychological practice. It is, however, not always clear to what extent these statements match current practices and school psychologists' self-perception of their professional role, as empirical data is often unavailable or limited. This study aims to address this gap by collecting empirical data on the scope of school psychological practice in Germany. In a mixed method study, we first applied the Delphi technique to develop a questionnaire in collaboration with school psychological experts from different federal states of Germany. Second, we collected information on federal policies through semi-structured interviews with regional experts. Third, we invited a representative sample of school psychologists to complete the questionnaire developed through the Delphi technique. In this first report, we focus on the Delphi procedure and overall results of the survey describing the scope of school psychological practice in Germany at a country-wide level. These findings provide a detailed characterization of the broad and heterogeneous scope providing an evidence-base for future research and political decision-making.