TTL may refer to:
Photography
- Through-the-lens metering, a camera feature
- Zenit TTL, an SLR film camera named for its TTL metering capability
Technology
- Time to live, a computer data lifespan-limiting mechanism
- Transistor–transistor logic, a family of integrated-circuit digital logic
- Differential TTL, a serial signaling standard based on TTL
- Turtle (syntax), a computer data format used in semantic web technologies
Other uses
- Taiwan Tobacco and Liquor, a state-owned manufacturer
- "TTL (Time to Love)", a single by South Korean girl group T-ara and boy band Supernova