TN may stand for:
- Thermonuclear.
- Air Tahiti Nui (IATA airline designator).
- Tamil Nadu (Indian state).
- Todo Noticias (Argentine TV channel).
- Tennessee (United States postal abbreviations).
- Telephone number
- Trunk Network (1ESS)
- Tête nucléaire (French nuclear warhead serial).
- Texas and Northern Railway (AAR reporting marks TN).
- Thursday Next.
- Trigeminal neuralgia.
- Tunisia (ISO 3166-1 alpha-2 country code).
- Twisted Nematic, a technology used in TFT LCD computer displays.
- True Neutral, an alignment in the role-playing game Dungeons & Dragons.
- The TN postcode area named after Tonbridge, England.
- The TN visa, a type of work visa for citizens of NAFTA countries working in the United States
- Transposon when immediately followed by a number.
- ISO 3166-2:IT code for the province of Trento in Italy.
- Women commonly use the term "TN" to refer to Tampons
