word | | Country name |
| conventional | Taiwan | conventional long form: none conventional short form: Taiwan local long form: none local short form: Taiwan former: Formosa |
| conventional | Tajikistan | conventional long form: Republic of Tajikistan conventional short form: Tajikistan local long form: Jumhurii Tojikiston local short form: Tojikiston former: Tajik Soviet Socialist Republic |
| conventional | Tanzania | conventional long form: United Republic of Tanzania conventional short form: Tanzania local long form: Jamhuri ya Muungano wa Tanzania local short form: Tanzania former: United Republic of Tanganyika and Zanzibar |
| conventional | Thailand | conventional long form: Kingdom of Thailand conventional short form: Thailand local long form: Ratcha Anachak Thai local short form: Prathet Thai former: Siam |
| conventional | Timor-Leste | conventional long form: Democratic Republic of Timor-Leste (pronounced TEE-mor LESS-tay) conventional short form: Timor-Leste local long form: Republika Demokratika Timor Lorosa'e [Tetum]; Republica Democratica de Timor-Leste ... |
| conventional | Togo | conventional long form: Togolese Republic conventional short form: Togo local long form: Republique togolaise local short form: none former: French Togoland |
| conventional | Tokelau | conventional long form: none conventional short form: Tokelau |
| conventional | Tonga | conventional long form: Kingdom of Tonga conventional short form: Tonga local long form: Pule'anga Tonga local short form: Tonga former: Friendly Islands |
| conventional | Trinidad and Tobago | conventional long form: Republic of Trinidad and Tobago conventional short form: Trinidad and Tobago |
| conventional | Tunisia | conventional long form: Tunisian Republic conventional short form: Tunisia local long form: Al Jumhuriyah at Tunisiyah local short form: Tunis |
| conventional | Turkey | conventional long form: Republic of Turkey conventional short form: Turkey local long form: Turkiye Cumhuriyeti local short form: Turkiye |