OECD support to strengthen tax systems across developing countries is continuing to expand and evolve in response to changing needs and emerging challenges, according to a new review of the OECD’s tax and development activities in 2025.

Tax Co-operation for Development 2025: Progress report provides an overview of the wide-ranging activities delivered last year by the OECD Centre for Tax Policy and Administration including the Global Forum on Transparency and Exchange of Information for Tax Purposes (Global Forum) to support developing countries in improving their tax systems. 

The report illustrates how the OECD co-operation with developing countries spans the full spectrum of tax support, covering policy analysis and design, internationally comparable data sets, tax administration support, international collaboration, as well as multilateral and bilateral capacity building.

The report shows that OECD programmes trained more than 22 000 officials in 2025, supported 88 countries in tax transparency and exchange of information activities and 28 countries through bilateral programmes on Base Erosion and Profit Shifting and transfer pricing. As part of Tax Inspectors Without Borders (TIWB), a joint OECD/UNDP initiative to strengthen tax audit capacity through technical assistance and capacity building, 14 new programmes were launched, including the first pilot programme on the Global Minimum Tax. Nine countries were provided with comprehensive bilateral support on VAT reform.

Through these capacity-building initiatives, developing countries have identified an additional EUR 48 billion in tax revenues from tax transparency measures, including through offshore tax investigations and voluntary disclosure programmes, in the period 2009-2024, while TIWB has helped raise an additional USD 2.72 billion since the initiative was launched in 2015. 

The report also highlights how OECD support is adapting in response to the changing needs of developing countries. In addition to comprehensive bilateral progammes, the OECD is expanding targeted support at the regional level, enabling peer networks to grow, as well as strengthening capacity building and technical experience sharing on specific aspects of taxation, including impact assessments, tax incentive design, and tax policy areas such as social protection financing and tobacco taxation. The OECD support is also broadening  beyond tax administrations and finance ministries, for example through a new programme to support the judiciary on international taxation. 

The report underscores the vital role of partnerships in delivering effective support on taxation, noting that many workstreams are delivered collaboratively, with key contributions from the United Nations Development Programme in respect to TIWB, and regional partners such as the African Tax Administration Forum and the Asian Development Bank. Financial contributions from Australia, the European Commission, France, Germany, Ireland, Italy, Japan, Korea, Luxembourg, Netherlands, Norway, Spain, Sweden, Switzerland, Türkiye and the United Kingdom, plus the contributions in kind of expertise from an even wider group of countries play a crucial role in enabling this work.