European XFEL GmbH aims to implement a Scientific Data Policy starting from 1 July 2017 in order to be prepared for the first beam operation of the European XFEL Facility. The main elements of the Scientific Data Policy comprise data ownership, data curation, data archiving, and open access to data. This Scientific Data Policy closely follows the recommendations of the PaN-data Europe Strategic Working Group laying out a common framework for scientific data management at photon and neutron facilities (Deliverable D2.1, PaN-data Europe, co-funded by the European Commission under the 7th Framework Programme). This version is valid until 31 December 2024.