This is a chronological list of world heavyweight boxing champions since the introduction of the Marquess of Queensberry rules

Marquess of Queensberry rules

The Marquess of Queensberry rules is a code of generally accepted rules in the sport of boxing. They were named so because John Douglas, 9th Marquess of Queensberry publicly endorsed the code, although they were written by a sportsman named John Graham Chambers. The code of rules on which modern...

: Bare knuckle champions who fought under London Prize Ring rules are not listed here, as they were predominantly British.
Champions were recognized by public acclamation. A champion in that era was a fighter who had a notable win over another fighter and kept winning afterward. Retirements or disputed results could lead to a championship being split among several men for periods of time.