| UAP | Unprocessed agricultural products |
| UDEAC | Union douanière et èconomique de l'Afrique centrale (see CACEU) |
| UN | United Nations |
| UNCED | United Nations Conference on Environment and Development |
| UNCITRAL | United Nations Commission on International Trade Law |
| UNCLOS | United Nations Convention on the Law of the Sea |
| UNCPC | United Nations Central (Provisional) Product classification |
| UNCTC | United Nations Commission on Trans-National Corporations |
| UNCTAD | United Nations Conference on Trade and Development |
| UNDP | United Nations Development Program |
| UNEP | United Nations Environment Program |
| UNESCO | United Nations Educational, Scientific and Cultural Organization |
| UNFCCC | United Nations Framework Convention on Climate Change |
| UNGA | United Nations General Assembly |
| UNGASS | United Nations General Assembly Special Session |
| UNIDO | United Nations Industrial Development Organization |
| UNIFEM | United Nations Development Fund for Women |
| UNISTE | United Nations Industrial Symposium on Trade Efficiency |
| UNRISD | United Nations Research Institute for Social Development |
| UPOV | International Union for the Protection of New Varieties of Plants (Fr. Union internationale pour la protection des obtentions végétales) |
| UR |
Uruguay Round |
| URAA | Uruguay Round Agreements Act (United States) |
| USITC | United States International Trade Commission |
| USTR | United States Trade Representative |
| UTL | Unilateral trade liberalisation |