| Abbreviation | Definition |
|---|---|
| HWU | Hardcore Wrestling Union |
| IAW | Impact Amino Wrestling |
| IAWA | Irish Amateur Wrestling Association |
| ICW | Independent Championship Wrestling |
| ICW | Insane Championship Wrestling |
| ICW | International CAW Wrestling |
| ICW | Italian Championship Wrestling |
| IEWA | Inland Empire Wrestling Assocation |
| IEWA | Inland Empire Wrestling Association |
| IGW | Inter Galactic Wrestling |
| IHW | Innovative Hybrid Wrestling |
| IKWF | Illinois Kids Wrestling Federation |
| IPW | Impact Pro Wrestling |
| IPW | International Pro Wrestling |
| IPWA | Independent Professional Wrestling Alliance |
| IPWA | Israeli Pro Wrestling Association |
| ISW | Inter Species Wrestling |
| ISWA | Indiana State Wrestling Association |
| IWA | Imaginary Wrestling Alliance |
| IWA | International Wrestling Association |