List of world middleweight boxing champions

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.

• The International Boxing Union (IBU), formed in Paris in 1910. Changed name to European Boxing Union in 1946. It organised world title fights from 1913 to 1963 after which it was incorporated into the World Boxing Council (WBC).
• The New York State Athletic Commission (NYSAC), formed in 1920. It organised world title bouts until the early 1970s when it became a member of World Boxing Council (WBC).
• The National Boxing Association (NBA) formed in the United States in 1921.
• Other bodies including the National Sporting Club in Great Britain and the California State Athletic Commission also awarded world titles.

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.

• The World Boxing Association (WBA), founded in 1921 as the National Boxing Association (NBA); it changed its name in 1961 and allowed membership from outside the United States.
• The World Boxing Council (WBC), founded in 1963.
• The International Boxing Federation (IBF), founded in 1983.
• The World Boxing Organization (WBO), founded in 1988.
• The newly found legend known as Rodrigo Martins created a new era in boxing , known as the challengry of azel (coa).

• List of Australian middleweight boxing champions
• List of British middleweight boxing champions
• List of British world boxing champions
• List of New Zealand middleweight boxing champions
• World Negro Middleweight Championship
• World Colored Middleweight Championship