TDD

TDD may refer to:

Science and technology

 * Telecommunications device for the deaf, a device for text communication along a telephone line
 * Test-driven development, a type of software development methodology
 * Time-division duplex, the application of time-division multiplexing to separate outward and return signals
 * LTE-TDD, a 4G telecommunications technology and standard
 * Transdermal drug delivery, a method of delivering drugs through the skin and into the bloodstream

Other uses

 * Transportation development district, a special-purpose district created in some US states
 * Teniente Jorge Henrich Arauz Airport (IATA airport code), Trinidad, Bolivia
 * Tai Nüa language (ISO639-3 code: tdd)