word | | Country name |
| former | Thailand | conventional long form: Kingdom of Thailand conventional short form: Thailand local long form: Ratcha Anachak Thai local short form: Prathet Thai former: Siam |
| former | Timor-Leste | ... Timor-Leste local long form: Republika Demokratika Timor Lorosa'e [Tetum]; Republica Democratica de Timor-Leste [Portuguese] local short form: Timor Lorosa'e [Tetum]; Timor-Leste [Portuguese] former: East Timor, Portuguese Timor |
| former | Togo | conventional long form: Togolese Republic conventional short form: Togo local long form: Republique togolaise local short form: none former: French Togoland |
| former | Tonga | conventional long form: Kingdom of Tonga conventional short form: Tonga local long form: Pule'anga Tonga local short form: Tonga former: Friendly Islands |
| former | Turkmenistan | conventional long form: none conventional short form: Turkmenistan local long form: none local short form: Turkmenistan former: Turkmen Soviet Socialist Republic |
| former | Tuvalu | ... conventional long form: none conventional short form: Tuvalu local long form: none local short form: Tuvalu former: Ellice Islands note: "Tuvalu" means "group of eight" referring to the country's eight traditionally ... |
| former | Ukraine | conventional long form: none conventional short form: Ukraine local long form: none local short form: Ukrayina former: Ukrainian National Republic, Ukrainian State, Ukrainian Soviet Socialist Republic |
| former | United Arab Emirates | conventional long form: United Arab Emirates conventional short form: none local long form: Al Imarat al Arabiyah al Muttahidah local short form: none former: Trucial Oman, Trucial States abbreviation: UAE |
| former | Uruguay | conventional long form: Oriental Republic of Uruguay conventional short form: Uruguay local long form: Republica Oriental del Uruguay local short form: Uruguay former: Banda Oriental, Cisplatine Province |
| former | Uzbekistan | conventional long form: Republic of Uzbekistan conventional short form: Uzbekistan local long form: Ozbekiston Respublikasi local short form: Ozbekiston former: Uzbek Soviet Socialist Republic |
| former | Vanuatu | conventional long form: Republic of Vanuatu conventional short form: Vanuatu local long form: Ripablik blong Vanuatu local short form: Vanuatu former: New Hebrides |