Middleweight is a weight class in professional boxing. Weight classes are categories in which competition is divided into to match competitors of the same size against each other. In professional boxing, middle weight boxers range from 154 pounds (70kg) to 160 pounds (73kg).
There is no exact history of this weight class, but it seems to have begun in the 1840s. During the era of bare-knuckle boxing, Tom Chandler and Dooney Harris contested for the inaugural middleweight championship in 1897. Chandler won this bout and was known as the American middleweight champion.
George Fulljames and Jack Nonpareil Dempsey were the first to contest in fight with gloves on.
The record for the most number of consecutive title defenses is held by Bernard Hopkins. He has had 20 defenses of the IBF Title.
The following table shows the current champions of this weight class.
| Sanctioning Body | Reign Began | Champion | Record | Defenses |
| WBA (super) | August 14, 2010 | Grennady Golovkin | 37-0-1 (33 KO) | 18 |
| WBA (regular) | October 22, 2017 | Ryota Murata | 13-1-0 (10 KO) | 0 |
| WBC | May 18, 2016 | Grennady Golovkin | 37-0-1 (33KO) | 3 |
| IBF | October 17, 2015 | Grennady Golovkin | 37-0-1 (33 KO) | 4 |
| WBO | December 20, 2015 | Billy Joe Saunders | 26-0-0 (12 KO) | 3 |
