T3

T3 or T-3 may refer to:

Medicine

T₃, in endocrinology, triiodothyronine, a thyroid hormone
- Polar T₃ syndrome, characterized by low levels of that hormone in polar explorers
T3 spinal nerve
Third thoracic vertebrae
An electrode site, in the 10–20 EEG system

Eastern Airways (IATA code)
Fuji T-3, a Japanese primary military trainer aircraft
T3, a model of the Oslo Metro OS T1000 train
Île-de-France tramway Line 3, in Paris
Bankstown Line (Sydney Trains), a former rail service in Sydney, Australia, numbered T3
Liverpool & Inner West Line, a rail service in Sydney numbered T3
Tatra T3, a tramcar
Trager-Bierens T-3 Alibi, a glider
T3 transit lane, a type of high-occupancy vehicle lane in Australia
Volkswagen Type 2 (T3), the third generation of the Volkswagen Transporter van
T3 tanker, a ship class
Slingsby T-3A Firefly, a former training aircraft of the United States Air Force
T3 road (Tanzania), a road in Tanzania
T3 road (Zambia), a road in Zambia
Heathrow Terminal 3

T3: Alliance, an investigative-public affairs program of TV5 in the Philippines
T3 (magazine), focusing on new and hi-tech gadgets
Terminator 3: Rise of the Machines, the third film in the Terminator series
Tekken 3, a 1997 fighting game in the Tekken franchise
Tiger 3, a 2023 Indian action thriller film in the YRF Spy Universe

Axiom T3 or T3 space, regular space in topology and related fields of mathematics
T3, a halogen light bulb form factor
T3 Technion Technology Transfer, the technology transfer office of the Technion Israel Institute of Technology
SPARC T3, a CPU introduced by Sun Microsystems in 2010
Digital Signal 3, or T3 line, a type of telecommunications service
Fletcher's Ice Island or T-3, an iceberg and scientific research station
T3 (company), the largest woman-owned advertising agency in the US
T3 (rapper), founding member of the band Slum Village
T3 (skyscraper), a skyscraper office building in Taichung, Taiwan
Tungsten T3, a device in the line of palmOne handhelds
Tokyo Teleport Town, a planned city on Odaiba, reclaimed land in Tokyo Bay
T3, a privatisation offering of the company Telstra
Talking tactile tablet, a touch sensitive device for visually impaired people
T3, part of the T-carrier telecommunications system, specifying a channel with a bandwidth of 44.736 Mbit/s, capable of carrying 672 voice calls simultaneously
Canon EOS Rebel T3, a digital camera
T3, a bedside television unit built by Hospedia
T-3, the third Jupiter Trojan survey, a subproject of the Palomar–Leiden survey
T3 (roller coaster) at Kentucky Kingdom
Sony Xperia T3, an Android smartphone
A tornado intensity rating on the TORRO scale
Tikka T3, a series of Finnish bolt-action rifles
T+3, "trade date plus three days" in financial markets