| Country | Legal system |
| United States | federal court system based on English common law; each state has its own unique legal system of which all but one (Louisiana, which is still influenced by the Napoleonic Code) is based on English common law; judicial review of legislative acts; has not accepted compulsory ICJ jurisdiction |
| United States Pacific Island Wildlife Refuges | the laws of the US where applicable apply |
| Uruguay | based on Spanish civil law system; accepts compulsory ICJ jurisdiction |
| Uzbekistan | based on civil law system; has not accepted compulsory ICJ jurisdiction |
| Vanuatu | unified system being created from former dual French and British systems; has not accepted compulsory ICJ jurisdiction |
| Venezuela | open, adversarial court system; has not accepted compulsory ICJ jurisdiction |
| Vietnam | based on communist legal theory and French civil law system; has not accepted compulsory ICJ jurisdiction |
| Virgin Islands | based on US laws |
| Wake Island | the laws of the US where applicable apply |
| Wallis and Futuna | the laws of France where applicable apply |
| West Bank | void |
| Western Sahara | void |
| World | all members of the UN are parties to the statute that established the International Court of Justice (ICJ) or World Court |
| Yemen | based on Islamic law, Turkish law, English common law, and local tribal customary law; has not accepted compulsory ICJ jurisdiction |
| Zambia | based on English common law and customary law; judicial review of legislative acts in an ad hoc constitutional council; has not accepted compulsory ICJ jurisdiction |
| Zimbabwe | mixture of Roman-Dutch and English common law; has not accepted compulsory ICJ jurisdiction |