| Abbreviation | Definition |
|---|---|
| HRP | Haute Randonne Pyrnenne |
| HSA | Home Sewing Association |
| HSC | Horse Showing Club |
| HSK | Hard Style Killers (stamps) |
| HSM | Hole Seeking Material |
| HSNW | Happy Stampers North West |
| HSR | HomeStar Runner |
| HTTC | Hard To The Core |
| HUNT | Heroes United Noble and True |
| IAA | Internationale Automobil Ausstellung (International Automobile Exhibition) |
| IBA | Independent Biker Association |
| IBBA | Inland Bird Banding Association |
| IBC | Incredible Blue Cards |
| IBET | Illinois Birders Exchanging Thoughts |
| IBF | International Brandy Federation |
| IBFC | IronBirds Flying Club |
| IBFCC | International Border Fancy Canary Club |
| IBFG | Irondequoit Bay Fish & Game Club |
| IBLE | Idaho Birders Linked Electronically |
| IBMC | International Brotherhood of Motorcycle Campers |