The World Boxing Association (WBA), formerly known as the National Boxing Association (NBA), is the oldest and one of four major organizations which sanction professional boxing bouts, alongside the World Boxing Council (WBC), International Boxing Federation (IBF) and World Boxing Organization (WBO). The WBA awards its world championship title at the professional level. Founded in the United States in 1921 by 13 state representatives as the NBA, in 1962 it changed its name in recognition of boxing's growing popularity worldwide and began to gain other nations as members.
The World Boxing Organization (WBO) is an organization which sanctions professional boxing bouts. It is recognized by the International Boxing Hall of Fame (IBHOF) as one of the four major world championship groups, alongside the World Boxing Association (WBA), World Boxing Council (WBC), and International Boxing Federation (IBF). The WBO's headquarters are located in San Juan, Puerto Rico.
Heavyweight is a weight class in combat sports and professional wrestling.
In boxing, the undisputed champion of a weight class is the boxer who simultaneously holds world titles from all recognized major organisations by each other and the International Boxing Hall of Fame. There are currently four major sanctioning bodies: WBA, WBC, IBF and WBO. There were many undisputed champions before the number of major sanctioning bodies recognizing each other increased to four in 2007, but there have only been 18 boxers to hold all four titles simultaneously.
Demetrius Cesar Andrade is an American professional boxer. He has held multiple world championships in two weight classes, at light middleweight and middleweight. As an amateur, he won the U.S. national championships and Golden Gloves twice each, a gold medal at the 2007 World Championships, and represented the U.S. at the 2008 Olympics; all in the welterweight division.
Donnie Liboon Nietes is a Filipino professional boxer. He is a world champion in four weight-classes, having previously held the WBO mini-flyweight title from 2007 to 2011; the WBO and The Ring magazine junior-flyweight titles between 2011 and 2016; IBF flyweight title from 2017 to 2018; and the WBO junior-bantamweight title from 2018 to 2019. He is the longest-reigning Filipino boxing world champion, surpassing in 2014 the record set in 1967 by Boxing Hall of Fame inductee Gabriel "Flash" Elorde. He was one of the first three Asian fighters with world titles in at least four weight classes alongside fellow Filipinos Manny Pacquiao and Nonito Donaire.
Vasiliy Anatolyevich Lomachenko, also spelled Vasyl Anatoliyovych Lomachenko is a Ukrainian professional boxer. He has held multiple world championships in three weight classes from featherweight to lightweight, including unified and lineal titles at lightweight.
Oleksandr Oleksandrovych Usyk is a Ukrainian professional boxer. He has held multiple world championships in two weight classes, including the unified heavyweight titles since 2021, and the Ring magazine title since 2022. He has also held the International Boxing Organization (IBO) title since 2021. Previously, he held the undisputed cruiserweight championship from 2018 to 2019, being the first boxer in that division to hold all four major world titles.
Óscar Rafael Valdez Fierro Jr. is a Mexican professional boxer. He is a former world champion in two weight classes, holding the WBC super featherweight title from 2021 to 2022, and the WBO featherweight title from 2016 to 2019. As an amateur boxer, Valdez qualified for the 2008 Olympics at the age of 17 and became the first Mexican Youth World Champion. Four years later, he qualified for the 2012 Summer Olympics.
Cecilia Carmen Linda Brækhus is a Norwegian professional boxer and former kickboxer. She reigned as the undisputed female welterweight boxing champion from 2014 to 2020, and is the first woman in any weight class to hold the WBA, WBC, IBF and WBO titles simultaneously. Brækhus is also one of only 11 boxers in history, female or male, to hold all four major world titles simultaneously. She also held the IBO title from 2016 to 2020.
John Riel Reponte Casimero is a Filipino professional boxer and a fulltime YouTuber. He has held world championships in three weight classes; including the IBF junior-flyweight title from 2012 to 2013; the IBF flyweight title in 2016; and the WBO bantamweight title from 2019 to 2022. Quadro Alas is Tagalog for four of a kind when translated, his moniker means Four Aces.
Dmitry Yurievich Pirog is a Russian politician and former professional boxer. In boxing he competed from 2005 to 2012, and held the World Boxing Organization (WBO) middleweight title from 2010 to 2012. Although his career was cut short due to a debilitating back injury, he is one of the few professional boxers to win a world championship and retire undefeated.
Naoya Inoue is a Japanese professional boxer. Nicknamed "The Monster", Inoue is known for his timing, speed, punching power, counter-punching ability, and body-punching ability, having a knockout ratio of 90.4% in world title matches, which is the highest KO rate in the history of world title matches. He is a four-division world champion, and only the second male boxer to become the undisputed champion in two different weight classes in the four-belt era. He is the first and only boxer in history to defeat all four major sanctioning organisation champions by knockout. He is the current, first, and only undisputed super bantamweight world champion, holding the WBC and WBO super bantamweight titles since July 2023, and the WBA (Super), IBF, and Ring super bantamweight titles since December 2023. He is also the former undisputed bantamweight world champion, having held the WBA (Super), IBF, and Ring magazine titles between 2019 and January 2023, and the WBC and WBO titles between 2022 and January 2023, and was the first undisputed bantamweight champion in the four-belt era. He previously held the WBA (Regular) bantamweight title from 2018 to 2019, the WBO super flyweight title from 2014 to 2018, and the WBC light flyweight title in 2014.
Janibek Alimkhanuly is a Kazakh professional boxer and unified middleweight champion who has held the WBO title since 2022, and the IBF title since October 2023. As an amateur, he won gold medals at the 2013 World Championships, 2013 Asian Championships and 2014 Asian Games. He also represented Kazakhstan at the 2016 Summer Olympics in the middleweight division, losing in the quarter-finals. He won the WBO Interim middleweight title on May 21, 2022, before being elevated to full champion on August 30, 2022, and he then won the IBF title on October 14, 2023.
David Light is a New Zealand professional boxer. As an amateur, he competed in the men's heavyweight division at the 2014 Commonwealth Games in Glasgow where he won the silver medal against Canada's Samir El-Mais. Professionally, Light is a former WBO World Crusierweight title contender, where he fought Lawrence Okolie in March 2023.
Kosei Tanaka is a Japanese professional boxer. He is a four-weight world champion, having held the WBO mini-flyweight title from 2015 to 2016; the WBO junior-flyweight title from 2016 to 2017; the WBO flyweight title from 2018 to 2020; and the WBO junior-bantamweight title in February 2024. Upon winning his first world title in only his fifth bout, he became the fastest Japanese fighter ever to become a world champion. Along with Vasyl Lomachenko, he is also the fastest ever fighter to win titles in three weight-classes, having accomplished the feat in only 12 bouts. He also surpassed Oscar De La Hoya to become the fastest four division champion, setting the bar at 21 fights.
Emanuel Navarrete Martínez is a Mexican professional boxer. He is a three-division world champion, having held the WBO junior featherweight title from 2018 to 2020, the WBO featherweight title from 2020 to 2023, and the WBO junior lightweight title since February 2023. As of December 2023, he is ranked as the world's number one active super featherweight by ESPN and BoxRec, and number one by the Transnational Boxing Rankings Board.
Naoya Inoue vs. Paul Butler, billed as Undisputed, was a bantamweight unification professional boxing match contested between WBA (Super), WBC, IBF, and The Ring champion, Naoya Inoue, and WBO champion, Paul Butler. Inoue knocked out Butler and became the undisputed bantamweight champion and the first since Enrique Pinder beat Rafael Herrera in 1972. The bout took place on 13 December 2022, at Ariake Arena in Tokyo, Japan.
Vartan Avetisyan
Grieghallen, Bergen, Norway
Timo Laine
Pabellon Camilo Cano, La Nucia, Spain
Vasyl Kondor
Sergei Gorokhov
Arena Riga, Riga, Latvia
Tomas Adamek
Gergo Horvath
Arena Armeec, Sofia, Bulgaria
Arthur Abraham 
Brondby Hallen, Brondby, Denmark
Baptiste Castegnaro
Slavisa Simeunovic
Farouk Daku
Giorgi Beroshvili
Marko Benzon
Oscar Ahlin
Tomas Kugler
Vygaudas Laurinkus