Harry S. Truman, thirty-third President of the United States

Hunter S. Thompson, American journalist and author

Hubble Space Telescope

Hastings, a town in East Sussex, England

High Speed Telegraphy, a radiosport

U.S. Robotics' HST (High-Speed Transfer) modem protocol

Hegemonic stability theory, a concept in international relations]

Heat-shrink tubing

Hospital Santo Tomas (Saint Thomas Hospital), a hospital in Panama City, Panama

High Street (Glasgow) railway station, Scotland with National Rail station code HST

Hypertrophy-specific Training, in weight lifting

Harmonized Sales Tax

Halloween Swim Team, A Los Angeles and Inland Empire based musical group

High Sierra Trail, a hiking trail in California's Sierra Nevada mountains

Harvard-MIT Division of Health Sciences and Technology

Helicopter support team, a team of 8 Landing Support Marines

Hawaii-Aleutian Standard Time Zone, UTC-10

Heritage Shunters Trust, a trading name of the South Yorkshire Railway Co Ltd

High Speed Train

InterCity 125, a British train often called an HST