This report reflects on ten years of Tax Inspectors Without Borders (TIWB), a joint initiative of the Organisation for Economic Co-operation and Development (OECD) and United Nations Development Programme (UNDP). It charts the evolution of the initiative from its formal launch in 2015 to 2025, highlighting key milestones and its expansion in response to the rapidly evolving international taxation and development landscape. 

The report examines the results achieved by TIWB over the past decade, in close collaboration with its dedicated partners, and how it has been instrumental in tackling illicit financial flows and strengthening domestic resource mobilisation. The report also reviews recent efforts to adapt and enhance the initiative to ensure it remains fit-for-purpose to support jurisdictions worldwide in an increasingly complex global environment. 

Looking ahead, the report explores how TIWB, in collaboration with new and existing stakeholders, will continue to innovate and explore opportunities to meet the rising demand for practical, hands-on capacity building from tax administrations worldwide.