The Grand Bargain recognises that greater data-driven transparency is essential for building trust, improving visibility and accountability of donors and aid organisations, and for enabling a more coordinated and effective response towards affected populations. Published before the Grand Bargain annual meeting in June 2020 and looking forward to the Grand Bargain’s five-year review, this report examines the progress of the transparency workstream in achieving its mission to increase the availability and use of timely, transparent, harmonised and open high-quality data on humanitarian financing to enable evidence-informed decision-making, greater accountability and learning. The report provides an analysis of progress on data publication and data use, documents lessons learnt from key workstream projects – in particular the pilot between the International Aid Transparency Initiative (IATI) and Financial Tracking Service (FTS) and the development of a data visualisation prototype in response to the Covid-19 pandemic – and proposes recommendations for workstream and signatory action in the coming year.