The United Nations Conference on Trade and Development (UNCTAD) is an intergovernmental organization within the United Nations Secretariat that promotes the interests of developing countries in world trade. It was established in 1964 by the United Nations General Assembly (UNGA) and reports to that body and the United Nations Economic and Social Council (ECOSOC). UNCTAD is composed of 195 member states and works with nongovernmental organizations worldwide; its permanent secretariat is in Geneva, Switzerland.

The primary objective of UNCTAD is to formulate policies relating to all aspects of development, including trade, aid, transport, finance and technology. It was created in response to concerns among developing countries that existing international institutions like GATT (now replaced by the World Trade Organization), the International Monetary Fund (IMF), and the World Bank were not properly organized to handle the particular problems of developing countries; UNCTAD would provide a forum where developing nations could discuss and address problems relating to their economic development.

One of UNCTAD's principal achievements was conceiving and implementing the Generalized System of Preferences (GSP), which promotes the export of manufactured goods from developing countries. In the 1970s and 1980s, UNCTAD was closely associated with the New International Economic Order (NIEO), a set of proposals that sought to reduce economic dependency and inequality between developing and developed countries.

UNCTAD conferences ordinarily take place every four years, with the first occurring in Geneva in 1964; fifteen subsequent meetings have taken place worldwide, with the most recent held in Bridgetown, Barbados from 3–8 October 2021 (albeit virtually, due to the COVID-19 pandemic).

UNCTAD has 400 staff members and a biannual (2010–2011) regular budget of $138 million in core expenditures and $72 million in extra-budgetary technical assistance funds. It is a member of the United Nations Development Group, a consortium of UN entities that work to promote sustainable socioeconomic development.