List of world middleweight boxing champions

Championship recognition.
1884–1910.
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.
1910–1961.
Championship awarding organizations.
An Australian version of the world title which existed briefly between 1914 and 1916 gained considerable credibility because its holder, Les Darcy, was widely believed to be best boxer in the world in this division.