List of world heavyweight boxing champions

At boxing's beginning, the heavyweight division had no weight limit, and historically the weight class has gone with vague or no definition. During the 19th century many heavyweights were 170 pounds (12 st 2 lb, 77 kg) or less, though others weighed considerably more. John L. Sullivan was the first widely recognized champion under Marquess of Queensberry rules. Known as the "Boston Strong Boy", Sullivan weighed around 200 pounds when in shape, and helped transition the sport from its bare-knuckle era. Sullivan would be defeated for the title by "Gentleman" Jim Corbett over 21 rounds on September 7, 1892, the first heavyweight titleholder solely under Queensberry rules.

In 1920, a de facto minimum weight for a heavyweight was set at 175 pounds (12 st 7 lb, 79 kg) with the standardization of a weight limit for the light heavyweight division. The addition of the cruiserweight division, which began in 1979, reset the de facto minimum, first to 190 pounds and then to 200 pounds in 2004 when boxing's major sanctioning bodies universally raised the weight limit at which they would recognize champions. The World Boxing Council created a new division called bridgerweight for boxers weighing between 200 and 225 pounds. As of June 2022, no other major organization has recognized the division.

The championship of the heavyweight division has been fractured or disputed at various times in its history. Until the 1960s, such disputes were settled in the ring, typically with alternate title claimants largely being forgotten. The rise of sanctioning organizations, however, have produced an environment where typically there is no single world heavyweight champion, with titleholders recognized by one of these organizations (a "World Champion") or more (a "Super Champion", a "Unified Champion", or, in the rare cases where the four most prominent organizations recognize the same boxer, an "Undisputed Champion").

Some title reigns are considered dubious owing to long periods of inactivity, the legitimacy of the organization granting championship recognition, and other factors. In 1967, for example, Muhammad Ali was denied a boxing license in every U.S. jurisdiction and stripped of his passport because of his refusal to be inducted into the armed forces. On April 29, 1967, his recognition as champion by both the World Boxing Association and World Boxing Council was withdrawn. Yet Ali remained the lineal champion and was recognized by The Ring and most boxing purists until his defeat in 1971. In pursuit of greater revenues, some organizations have now adopted a practice of simultaneously recognizing multiple champions in a weight division, creating a situation in which a champion may be unable not only to secure recognition from multiple sanctioning bodies but to secure sole recognition from a single one.

Public acclamation: 1884 to 1921
World champions were initially recognized by wide public acclamation, with heavyweight champions winning and losing championship recognition solely in the ring. Retirements periodically resulted in no one, true champion being recognized, while in other cases new champions were proclaimed only to see a previously recognized champion come out of retirement. Public interest in boxing resulted in a true champion being determined by means of title claimants facing one another in the ring, with the winner being recognized as world champion.

The Ring magazine: 1922 to present
The Ring has recognized heavyweight champions during two periods, commencing with its inaugural issue in 1922 and continuing until the 1990s, then again from 2002 to the present day. Under its original policy, a champion earned championship recognition in the ring, defeating the preceding champion or winning a bout between its top rated contenders. Once awarded, championship recognition could be lost only by death, retirement, or loss in the ring. In 2012, this policy was revised so championship recognition could be more easily awarded or withdrawn.

Sanctioning bodies: 1921 to present
The National Boxing Association (NBA) was organized in 1921 to serve as a regulating authority for boxing in the United States. The prominence of New York City as the epicenter of boxing would lead to its state boxing regulatory body, the New York State Athletic Commission (NYSAC) joining the NBA in recognizing world champions in each weight class. A third entity, the European Boxing Union (IBU) would follow suit, but with limited exception in the heavyweight division the three organizations recognized the same champion.

At its 1962 convention, the NBA's non-United States members exploited a membership rule and took effective control of the organization, rebranding it as the World Boxing Association. The now WBA would be joined the following year by a combination of state and national boxing commissions (including the NYSAC and IBU) to form a new organization, the World Boxing Council (WBC). In time, each organization would have its own spin-off sanctioning organization break from its ranks: the United States Boxing Association, which disassociated with the WBA in the late 1970s and became the International Boxing Federation in 1983, and the World Boxing Organization, whose members would split from the WBC in 1988. Today there are over a dozen sanctioning organizations which recognize champions and sanction world championship bouts, but the WBA, WBC, IBF, and WBO are recognized by the International Boxing Hall Of Fame as major sanctioning bodies.

List of combined reigns
As of May 26, 2024.

Keys:
 * Active title reign
 * Reign has ended
 * WBO heavyweight title bouts before August 23, 1997 are not includedSeveral IBHOF inductees’ professional boxing records printed in the organization's official record books indicate that IBHOF did not recognize WBO as a major organization until at least August 23, 1997:


 * IBHOF official record book, 1997 edition
 * Sugar Ray Leonard's opponent Thomas Hearns, who was defending the WBO super middleweight title against him on 12 June 1989, is not marked as World Champion
 * IBHOF official record book, 1999 edition
 * Sugar Ray Leonard's opponent Thomas Hearns, who was defending the WBO super middleweight title against him on 12 June 1989, is not marked as World Champion
 * IBHOF official record book, 2002 edition
 * Sugar Ray Leonard's opponent Thomas Hearns, who was defending the WBO super middleweight title against him on 12 June 1989, is not marked as World Champion
 * IBHOF official record book, 2006 edition
 * Sugar Ray Leonard's opponent Thomas Hearns, who was defending the WBO super middleweight title against him on 12 June 1989, is not marked as World Champion
 * Michael Carbajal's opponent Josue Camacho, who was defending the WBO junior flyweight title against him on 15 July 1994, is not marked as World Champion
 * Michael Carbajal's opponent Jorge Arce, who was defending the WBO junior flyweight title against him on 31 July 1999, is marked as World Champion
 * IBHOF official record book, 2011 edition
 * Sugar Ray Leonard's opponent Thomas Hearns, who was defending the WBO super middleweight title against him on 12 June 1989, is not marked as World Champion
 * Michael Carbajal's opponent Josue Camacho, who was defending the WBO junior flyweight title against him on 15 July 1994, is not marked as World Champion
 * Ricardo Lopez's opponent Alex Sanchez, who was defending the WBO minimumweight title against him on 23 August 1997, is marked as World Champion
 * Michael Carbajal's opponent Jorge Arce, who was defending the WBO junior flyweight title against him on 31 July 1999, is marked as World Champion

List of individual reigns
The list includes The Ring belt. Career total time as champion (for multiple time champions) does not apply.

Keys:
 * Active Title Reign
 * Reign has ended
 * The WBO heavyweight title bouts before August 1997 are not included