| Abbreviation | Definition |
|---|---|
| GYS | Greenville Youth Sports |
| GYS | Gulf Youth Sport |
| GYSD | Global Youth Service Day |
| GYTS | Global Youth Tobacco Surveys |
| GYU | Global Youth United |
| GYW | Ghana Youth Watch |
| GYW | Global Youth Work |
| GYW | Green Youth Wrestling |
| HAPPY | Healthy Active Positive Purposeful Youth |
| HAPPY | Healthy Activities Partnership Program for Youth |
| HAPPY | Healthy Alternative Program for Preschoolers Youth |
| HAPPY | Heathcote Alliance for Preserving Prosperity and Youth |
| HAPPY | Helping Advocate Productive and Progressive Youth |
| HAPPY | HIV AIDS Prevention Promotion Youth |
| HARMONY | Harmonization of At Risk Multisite Observational Networks for Youth |
| HAY | Homes Art Youth |
| HAYO | Holland Area Youth Orchestra |
| HAYS | Hebersham Aboriginal Youth Service |
| HBTY | Heichal Baoranim Temple Youth |
| HBY | Herne Bay Youth |