THG

THG may refer to:

Businesses

 * THG plc, an e-commerce company
 * THG Sports, a sports ticketing and corporate hospitality company
 * Hanover Insurance, by NYSE symbol

Other uses

 * Tetrahydrogestrinone, an anabolic steroid
 * The Humble Guys, a 1990s IBM PC cracking group
 * Third-harmonic generation, in nonlinear optics
 * Thangool Airport, by IATA code