T5 or T-5 can refer to:

• T5 engine
• T5 Statement of Investment Income, a Canadian tax form
• Terminal 5 at London Heathrow Airport
• Borg-Warner T-5 transmission
• Tungsten T5, a PDA

• Fifth thoracic vertebrae
• T5 spinal nerve
• Tele 5 (Poland) a TV channel
• Thunderbird 5, in the series Thunderbirds
• Topological space
• fluorescent lamp, with high output
• Trikke 5, 3 wheeled cambering vehicle
• Volkswagen Transporter van
• Telecinco, a Spanish TV channel
• Turkmenistan Airlines, IATA airline designator
• Traveller (role-playing game) Fifth Edition of the role-playing game Traveller. AKA: T5