| Country | Legal system |
| Timor-Leste | on 29 March 2009, the president promulgated the Timor-Leste penal code; UN-drafted legal system based on Indonesian law remains in place for civil codes, but is to be replaced by civil codes based on Portuguese law; these codes have passed but have not been promulgated; has not accepted compulsory ICJ jurisdiction |
| Togo | French-based court system; accepts compulsory ICJ jurisdiction with reservations |
| Tokelau | New Zealand and local statutes |
| Tonga | based on English common law; has not accepted compulsory ICJ jurisdiction |
| Trinidad and Tobago | based on English common law; judicial review of legislative acts in the Supreme Court; has not accepted compulsory ICJ jurisdiction |
| Tunisia | based on French civil law system and Islamic law; some judicial review of legislative acts in the Supreme Court in joint session; has not accepted compulsory ICJ jurisdiction |
| Turkey | civil law system derived from various European continental legal systems; note - member of the European Court of Human Rights (ECHR), although Turkey claims limited derogations on the ratified European Convention on Human Rights; has not accepted compulsory ICJ jurisdiction |
| Turkmenistan | transitioning to civil law system and influenced by Islamic law tradition; has not accepted compulsory ICJ jurisdiction |
| Turks and Caicos Islands | based on laws of England and Wales with a few adopted from Jamaica and The Bahamas |
| Tuvalu | English common law supplemented by local customary law; has not accepted compulsory ICJ jurisdiction |
| Uganda | based on English common law and customary law; accepts compulsory ICJ jurisdiction with reservations |
| Ukraine | based on civil law system; judicial review of legislative acts; has not accepted compulsory ICJ jurisdiction |
| United Arab Emirates | based on a dual system of Sharia and civil courts; has not accepted compulsory ICJ jurisdiction |
| United Kingdom | based on common law tradition with early Roman and modern continental influences; has nonbinding judicial review of Acts of Parliament under the Human Rights Act of 1998; accepts compulsory ICJ jurisdiction with reservations |