HTH may stand for:

  • hand-to-hand or mêlée combat
  • Heavy Transport Helicopter is a program study into the European Heavy Lift Helicopter Program by Eurocopter
  • Helix-turn-helix, in proteins, a major structural motif capable of binding DNA
  • Gary and Jerri-Ann Jacobs High Tech High Charter School, a public charter high school in San Diego, USA
  • High-Test Hypochlorite, typically sodium or calcium hypochlorite, a strong chlorinating agent used for swimming pools and water wells
  • Highway to Hell, a 1979 album by AC/DC
    • Highway to Hell (song)
  • Hilltop Hoods, an Australian hip hop group
  • Hollywood Tower Hotel, a fictional location featured in the Tower of Terror rides
  • Hometown Heroes
  • Hewitt Trussville High
  • Internet slang for "Hope This/That Helps", "Happy To Help", "Hit The Hay", "How The Hell?", "Heart To Heart", or "Hand To Hand"