The Open Science Training Handbook (ver. 1) is intended for anyone who wishes to host Open Science training events or introduce Open Science concepts to discipline-training events, in order to foster the uptake of Open Research practices. This includes librarians, infrastructure providers, research support officers, funders, policy makers and decision makers. The handbook is also meant for all those who have regular or occasional contact with researchers (and other stakeholders) and wish to share their Open Science knowledge, either as part of regular working duties or as extra investment of time. Importantly, it will be of use to those hosting training events to foster reuse, participation, efficiency, equity, and sharing in research, regardless whether they ascribe to (or wish to use) the term Open Science.