| Abbreviation | Definition |
|---|---|
| HSOCF | Henry Shaw Ozark Corridor Foundation |
| HSP | Historical Society of Pennsylvania |
| HSPA | Habitat Special Programme for Africa |
| HSSA | Humane Society of Southern Arizona |
| HSUS | Humane Society of the United States |
| HSWM | Humane Society of the White Mountains |
| HSWM | Humane Society of Western Montana |
| HTAC | Help The Afghan Children |
| HTC | Healing The Children |
| HTC | Help The Children |
| HTCNE | Healing The Children, North East |
| HTG | Help Them Grow |
| HTG | Huronia Trails and Greenways |
| HTI | Hand Tools Institute |
| HTNA | Hyperbaric Technicians and Nurses Association |
| HTTA | Hawaii Technology Trade Association |
| HTTA | High Technology Trade Association |
| HTWF | Healing Touch Worldwide Foundation |
| HUA | Hearts United for Animals |
| HUF | Hispanic United Fund |