| Abbreviation | Definition |
|---|---|
| GRT | Grasser Racing Team |
| GRT | Gumbo Racing Team |
| GRV | Greyhound Racing Victoria |
| GRV | Greyhound Racing Victoria's |
| GSR | Grand Slam Racing |
| GSR | Grand Sport Racing |
| GSRS | Granite State Race Services |
| GSRT | Granite State Racing Team |
| GTBR | Glen Tay Block Race |
| GTBR | Great Texas Balloon Race |
| GTG | Generic Trace Generator |
| GTR | Gran Tourismo Racing |
| GTR | Gran Turismo Racer |
| GTR | Grand Tour Racing |
| GTR | Grand Tourismo Race |
| GVF | Grace Valley Fellowship |
| HARC | Heritage Arabian Racing Club |
| HART | Honda of America Race Team |
| HHR | Historical Horse Racing |
| HJRT | Humpuss Junior Racing Team |