At the second meeting of his High-Level Advisory Board on Mediation on 18 June 2018 in Helsinki, United Nations Secretary-General António Guterres tasked the Mediation Support Unit (MSU) in the United Nations Department for Political and Peacebuilding Affairs (UN DPPA) and the Centre for Humanitarian Dialogue (HD) to develop a Toolkit on the role of digital technologies in armed conflict mediation. Over the course of several months, MSU/UN DPPA and HD engaged with a range of mediation experts – through a dedicated survey, consultations and in-person focus group meetings – and desk research carried out to inform the development of the Toolkit. The report represents the outcome of this work.