As in the 1980s, the 1990s in boxing's popularity focused on all divisions. When 80s legends Sugar Ray Leonard, Thomas Hearns, as well as others retired, newer superstars filled the void: Pernell Whitaker, Julio César Chávez, in the early 90s, Oscar De La Hoya, Félix Trinidad, Roy Jones Jr., and Floyd Mayweather, Jr., in the mid to late 90s.
As for the heavyweight division, Mike Tyson's reign ends prematurely with the upset loss to Buster Douglas. Former cruiserweight champion, Evander Holyfield took over as the undisputed champion of the division, and later built a rivalry against former Olympic silver medalist, Riddick Bowe. The later 90s was dominated by Lennox Lewis who unified the division in 1999.
The 90s also saw the emergence of the battles between the British super middleweight fighters Chris Eubank, Michael Watson and Nigel Benn, all of whose careers ended in tragedy.
List of notable fights by year 
- February 10 Buster Douglas upsets Mike Tyson by 10th-round KO in Tokyo, to become the undisputed heavyweight champion of the world. Douglas was a 42–1 underdog.
- March 31 – Thunder Meets Lightning: Julio César Chávez defeats Meldrick Taylor by 12th-round KO, for the WBC-IBF light welterweight unification. There was controversy as referee Richard Steele stops the contest with 2 seconds left in the bout and Taylor ahead on the scorecards.
- August 11 Pernell Whitaker defeats Juan Nazario by first-round knockout to unify the WBA,WBC,IBF belts and becomes the undisputed lightweight champion of the world.
- October 25 Buster Douglas's short reign as heavyweight champion ends as he loses to Evander Holyfield by third-round KO. Douglas was very noticeably out of shape, despite being in pinnacle shape in the Tyson fight, six months before.
- November 11 Julian Jackson wins by stunning knockout over Herol Graham by a devastating 4th-round KO for the vacated WBC middleweight title. Graham, ahead in the fight, was knocked out by Jackson by a devastating right hand and was out for five minutes.
- November 18 Chris Eubank wins the WBO middleweight title by beating Nigel Benn by 9th round TKO.
- March 13 Michael Carbajal wins by KO against Humberto González to unify the IBF and WBC Flyweight belts. Carbajal got knocked down twice during the fight and came back to knock out Gonzalez late in the seventh round.
- May 22 Roy Jones Jr. defeats Bernard Hopkins by unanimous decision to win the vacated IBF middleweight title.
- September 10 Julio César Chávez and Pernell Whitaker's fight for the WBC welterweight title ends in a controversial draw, despite Whitaker seemingly dominating the fight.
- October 1 Lennox Lewis beats Frank Bruno in the seventh round by a technical knockout. Lewis was defending his WBC Heavyweight title. It was the first time that two British-born boxers had fought for the world heavyweight title.
- November 6 Evander Holyfield defeats Riddick Bowe by majority decision in their rematch for the WBA and IBF heavyweight titles. A man parachutes to the corner of the ring during the fight and starts a mini riot, the fight is later labelled the Fan Man Fight.
- January 29 – Frankie Randall causes Julio César Chávez his first defeat in 91 professional bouts, winning the WBC world Jr. Welterweight title in the process, by a split decision in 12 rounds.
- April 22 Michael Moorer defeats Evander Holyfield to win the Lineal,WBA,& IBF Heavyweight Championship
- September 24 Lennox Lewis loses his WBC championship and undefeated record after getting knocked out by Oliver McCall in front of his home crowd in London
- November 5 George Foreman at 45 years old becomes the oldest heavyweight champion defeating Michael Moorer by knockout in round 10, with Foreman behind in all the scorecards.
- November 18 Roy Jones Jr. defeats James Toney by a lopsided unanimous decision to win the IBF super middlweight championship
- February 15 Nigel Benn defeats Gerald McClellan by a tenth round TKO for the WBC super middleweight title after being knocked through the ropes in the first round, and knocked down again in the eighth round. McClellan is counted on his knees, then loses consciousness in the ring and is transported to hospital, where he falls into a coma and suffers extensive brain damage, losing his eyesight and becoming 80 percent deaf.
- May 6 Oscar De La Hoya unifies the WBO and IBF Lightweight titles in his victory against Rafael Ruelas.
- August 19 Mike Tyson defeats Peter McNeeley in his first comeback fight.
- November 4 Riddick Bowe knockout Evander Holyfield in the 8th round
- February 7 Lennox Lewis regains the now vacant WBC heavyweight title against his only conqueror Oliver McCall, in a bizarre bout, where McCall refuses to fight after the third round and begins to cry in the ring forcing the referee to stop the fight in the fifth round
- March 1 Sugar Ray Leonard returns to the ring after a six-year layoff at the age of 41, but loses a fifth round TKO against Héctor Camacho and retires for good after the fight.
- March 21 Roy Jones Jr. loses his WBC light heavyweight title by disqualification to Montell Griffin for hitting after the fighter was down, suffering the first loss in his career, Jones Jr. was behind on two score cards.
- June 28 Evander Holyfield wins by disqualification over Mike Tyson, after Tyson tries to bite Holyfield's ear twice, to retaliating to Holyfield's headbutts.
- August 7 Roy Jones Jr. regains his WBC light heavyweight title by first-round knockout in his rematch against Montell Griffin.
- March 13 WBA and IBF champion Evander Holyfield and WBC champion Lennox Lewis meet in a unification heavyweight bout in Las Vegas, but the fight ends in a controversial draw.
- August 5 Roy Jones Jr. defeats Reggie Johnson and successfully unifies the light heavyweight division becoming the undisputed champion of the division.
- September 18 In what was billed as the Fight of the millennium, Félix Trinidad defeats Oscar De La Hoya by a controversial majority decision. The fight generated 1.4 million pay per view buys generating a record for a non heavyweight fight.
- November 13 Lennox Lewis becomes the undisputed heavyweight champion of the world in his rematch against Evander Holyfield by unanimous decision.