THD

THD may refer to:
 * Total harmonic distortion, a measure of the distortion of an audio signal
 * Total Hi Def (Total HD), an optical disc format
 * Th.D. or D.Th. or D.Theol., a Doctor of Theology degree
 * Thames Ditton railway station, Surrey, National Rail station code
 * THD Electronics, a guitar amplifier manufacturer
 * Transanal hemorrhoidal dearterialization, a surgical procedure
 * That Handsome Devil, an American alternative rock band
 * The IATA airport code for Thọ Xuân Airport
 * The ICAO airline code for Thai Smile
 * Transmitting Heading Device