| Championshipname: | International Junior Heavyweight Championship |
| Currentholder: | Seiki Yoshioka |
| Won: | March 3, 2024 |
| Promotion: | Pro Wrestling Zero1 |
| Created: | June 29, 2002 |
| Mostreigns: | Ikuto Hidaka (5) |
| Firstchamp: | Leonardo Spanky |
| Longestreign: | Ikuto Hidaka (540 days) |
| Shortestreign: | Tatsuhito Takaiwa (<1 day) |
| Pastnames: |
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The International Junior Heavyweight Championship is a professional wrestling championship in Japanese promotion Pro Wrestling Zero1 (Zero1, formerly Pro Wrestling Zero-One and Pro Wrestling Zero1-Max), contested exclusively among junior heavyweight (<100kg (200lb)) wrestlers. It was originally created on June 29, 2002, as the NWA/UPW/Zero-One International Junior Heavyweight Championship, symbolizing Pro Wrestling Zero-One (Zero-One)'s relationship with the National Wrestling Alliance (NWA) and Ultimate Pro Wrestling (UPW); Leonardo Spanky defeated Smelly to become the first champion.[2] When Zero-One left the NWA on October 31, 2004, the title was renamed to incorporate Steve Corino's Pro Wrestling World-1 (Word-1), becoming the Zero-One/UPW/World-1 International Junior Heavyweight Championship. The name was again altered when the newly renamed Pro Wrestling Zero1-Max (Zero1-Max) joined the AWA Superstars of Wrestling (AWA) alliance on February 28, 2005, with the title becoming known as the AWA/Zero1-Max/UPW/World-1 International Junior Heavyweight Championship. On August 26, 2006, after Minoru Fujita won the annual Tenkaichi Jr. tournament, Fujita renamed the championship to the AWA World Junior Heavyweight Championship. When Zero1-Max left the AWA on December 15, 2007, it was renamed again to the Zero1-Max International Junior Heavyweight Championship. Finally, when the company changed its name to Pro Wrestling Zero1 in 2008, the championship followed and became known as the Zero1 International Junior Heavyweight Championship.
There have been a total of 27 recognized champions, who have had a combined 37 official reigns. The current champion is Seiki Yoshioka who is in his first reign.
As of, .
| † | Indicates the current champion | |
|---|---|---|
| ¤ | The exact length of at least one title reign is uncertain, so the shortest length is considered. |
| Rank | Wrestler | No. of reigns | Combined defenses | Combined days |
|---|---|---|---|---|
| 1 | 5 | 16 | 1,239 | |
| 2 | 3 | 12 | 918 | |
| 3 | 1 | 2 | 481 | |
| 4 | 2 | 4 | 421 | |
| 5 | 1 | 2 | 403 | |
| 6 | 1 | 8 | 349 | |
| 7 | 1 | 1 | 310 | |
| 8 | 3 | 5 | 293 | |
| 9 | 1 | 2 | 266 | |
| 10 | 1 | 3 | 265 | |
| 11 | 1 | 0 | 259 | |
| 12 | 2 | 4 | 257 | |
| 13 | 1 | 2 | ¤242 | |
| 14 | 1 | 2 | 232 | |
| 15 | 1 | 1 | 225 | |
| 16 | 1 | 3 | 222 | |
| 17 | 1 | 5 | 213 | |
| 18 | 1 | 4 | 195 | |
| 19 | 1 | 3 | 155 | |
| 20 | 1 | 1 | 135 | |
| 21 | Sean Guinness | 1 | 1 | 129 |
| 22 | 1 | 1 | 128 | |
| 23 | Seiki Yoshioka † | 1 | 0 | + |
| 24 | 1 | 0 | 117 | |
| 25 | 1 | 3 | 79 | |
| 26 | 1 | 0 | 58 | |
| 27 | 1 | 1 | 45 | |