This study aims to collect empirical data on the scope of school psychological practice in Germany. In a mixed method study, we first plan to rely on the Delphi technique to develop a questionnaire in collaboration with school psychological experts from 16 federal states of Germany. Second, we plan to collect information on federal policies through semi-structured interviews with regional experts. Finally, we plan to invite a representative sample of school psychologists to complete the questionnaire developed through the Delphi technique. We submitted a registered report for this study to the Canadian Journal of School Psychology and received a stage 1 in principle approval on November 21st 2020. Any deviations from the pre-specified research plan will be documented on this OSF project page.