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