A comeback (or come-from-behind) is an occurrence of an athlete or sports team engaged in a competition overcoming a disadvantage in points, position, or series. It has been described as "the single greatest aspect of competition that most embodies the spirit of what makes sport extraordinary". It has been observed in spectator sports that "dramatic play seems to involve both players; cheering would often escalate when one player gained momentum, and then his/her opponent suddenly turned the tables and made a comeback", with such a result drawing more enthusiasm than one competitor defeating the other without giving up any points.Todd Harper, The Culture of Digital Fighting Games: Performance and Practice (20130), p. 43. Fans are likely to feel better about a team that loses after staging a "comeback that fell just short" than a team that lost by the same score after having played evenly throughout the match and then allowed the other team the winning score at the end.Tobias J. Moskowitz, L. Jon Wertheim, Scorecasting: The Hidden Influences Behind How Sports Are Played and Games Are Won (2012), p. 77-78.

In some sports, particularly those regulated by a game clock, the time that it takes to score points makes a comeback impossible when there is too great a point disadvantage to overcome in the time remaining. It has been noted, however, that in "some sports, such as tennis or baseball, a comeback is possible until the very last point, regardless of what the deficit might be".Francesco Duina, Winning: Reflections on an American Obsession (2010), p. 30. Many sporting news outlets have compiled lists of "greatest comebacks" for various sports.

Some academic study of sports comebacks has been conducted. One study indicated that in the sports of basketball, football and ice hockey, the team leading in points at the beginning of the final period of play wins the game 80% of the time, with the trailing team overcoming this disadvantage 20% of the time.Paramjit S. Gilla, "Late-Game Reversals in Professional Basketball, Football, and Hockey", The American Statistician, Vol. 54, No. 2 (May, 2000), pp. 94–99, DOI:10.1080/00031305.2000.10474518. Another determined that the home team advantage has a significant impact on the probability of a team engineering a late comeback, noting that for professional basketball teams, "the home team is more than three times as likely to make a fourth-quarter comeback than is the visiting team (33.3% versus 10.5%)".Harris Cooper, Kristina M. Deneve, and Frederick Mosteller, "Predicting professional sports game outcomes from intermediate game scores", CHANCE, Volume 5, Issue 3–4, 1992, p. 18-22, DOI:10.1080/09332480.1992.10554981. A comeback by one competitor may coincide with, or be alternatively characterized, as a "choke" by the opponent allowing the comeback.Alan W. Heaton and Harold Sigall, "The “Championship Choke” Revisited: The Role of Fear of Acquiring a Negative Identity", Journal of Applied Social Psychology, Vol. 19, No. 12 (September 1989), p. 1019–1033, DOI: 10.1111/j.1559-1816.1989.tb01236.x. See, e.g., Tony Lee, Greatest Rivalries in Sports (2014), p. 19: "Red Sox fans called it the greatest comeback in sports history. Or, if they wanted to insult the hated Yankees, they called it the biggest choke in sports history"; Sal Maiorana, Buffalo Bills: The Complete Illustrated History (2010), p. 131: "[T]he Bills somehow came together and pulled off the greatest comeback the NFL has ever seen..." but "'It was the biggest choke in history', Houston cornerback Cris Dishman said".

The term "comeback" can also refer to performers returning to (or attempting to return to) their former level of competition after an adverse event that seems to threaten their careers and/or a lengthy period of absence, whether that hiatus was caused by voluntary retirement, injury, other medical reason and/or some other circumstance(s). Use of the term in this context can also be found in fields such as politics and the entertainment industry, in addition to sports.

American football

There is no official definition or statistic for comebacks in American football, but many fans note the ability of certain teams to mount a comeback late in the game. A team may have a second-half comeback after having fallen well behind in the first half, or a fourth-quarter comeback after having fallen well behind with only one quarter of play remaining.

Certain comebacks are particularly historically significant. For example, in American football, "The Comeback" refers to a specific NFL playoff game between the Buffalo Bills and the Houston Oilers played on January 3, 1993. It featured the Bills recovering from a 32-point deficit shortly after halftime to win in overtime, 41–38, the largest comeback in terms of points (at that time) in NFL history, postseason or regular season.R. D. Griffith, To the NFL: You Sure Started Somethin' (2012), p. 50. This has been referred to as "the greatest comeback in NFL history".Dustin Long, Greatest Comebacks in Sports (2014), p. 25–27. The record was later broken by the 2022-23 Vikings in a Week 15 game coming back from a 33 point deficit at halftime and later scored 32 unanswered points outscoring their opponent, the Indianapolis Colts 39–3, breaking the 1992-93 Bills record for either playoffs or regular season. Another prominent example of a comeback came in Super Bowl LI, played on February 5, 2017, where the New England Patriots, down by 25 points (28–3) in the third quarter, would eventually defeat the Atlanta Falcons in overtime, 34–28, for its second championship title in three years. The Patriots' 25-point comeback was the largest in Super Bowl history.

The 2006 Michigan State vs. Northwestern football game featured the largest comeback in NCAA Division I-A history, when the Michigan State Spartans rallied to score 38 unanswered points to beat the Northwestern Wildcats 41–38 after falling behind 38–3 with 9:54 left in the 3rd quarter."Spartans stun Cats for biggest comeback in I-A history", ESPN (October 24, 2006).

In the 2006 Insight Bowl, the Texas Tech Red Raiders completed the largest comeback in NCAA Division I-A Bowl Game history. The Minnesota Golden Gophers led 38–7 with 7:47 left in the 3rd quarter. Texas Tech quarterback Graham Harrell scored two touchdowns, running back Shannon Woods scored another TD, and kicker Alex Trlica hit the game-tying 52-yard field goal as time expired in regulation. Gophers quarterback Bryan Cupito led a drive capped off by a Joel Monroe field goal. Shannon Woods ended the game with a 3-yard rushing touchdown to complete the thrilling comeback.

In the 2016 Valero Alamo Bowl, the TCU Horned Frogs tied the aforementioned Texas Tech Red Raiders for the largest comeback in NCAA Division I-A Bowl Game history. The Oregon Ducks led 31–0 at halftime. The Ducks' star quarterback Vernon Adams Jr. left the game with an injury. TCU backup QB Bram Kohlhausen (who was playing for starter Trevone Boykin as he was suspended for off-the-field issues) led an unbelievable 31-point second half to tie the game. The Frogs ended up winning the game 47–41 in 3OT after the Ducks failed to convert on 4th Down. In 1994, a college football game known as the Choke at Doak between the Florida Gators and Florida State Seminoles tied the NCAA record for the biggest fourth-quarter comeback at 28 points.

The largest fourth-quarter comeback in the history of the NFL came in Week 9 of the 1987 NFL season, as the St. Louis Cardinals came back from a 28-3 deficit with 12:42 remaining in the final quarter, scoring 28 straight points on top of the Tampa Bay Buccaneers' defense to take a 31-28 lead with 2:01 remaining in the game; a field goal attempt from the Buccaneers' kicker Donald Igwebuike struck the crossbar as the game clock expired, that 25-point difference remaining the largest comeback in just the fourth quarter in NFL history.

Association football The ability for a comeback to occur in association football is limited by the game clock of 90 minutes per match. Association football often settles knockout rounds using two-legged ties, in which the second leg can be described as a comeback for the winner of the tie if they had lost the first leg.

A notable example of such a comeback happened on 21 December 1957. With 27 minutes left, Charlton Athletic F.C. were losing 5–1 to Huddersfield Town A.F.C. and down to ten men. However, they scored six more goals to win 7–6.

Another example is Liverpool's comeback against AC Milan in the 2005 UEFA Champions League final in which Liverpool came back from a 3–0 deficit in the first half after scoring three goals in 7 minutes to make it 3–3, eventually winning the match 3–2 on penalties. The match was later dubbed 'The Miracle of Istanbul'.

An example of a record breaking comeback is FC Barcelona (6–1, 6–5 on aggregate) against Paris Saint-Germain F.C. in the UEFA Champions League round of 16 on March 8, 2017 at Camp Nou, Barcelona. It was the first time in UEFA Champions League history that a team had overcome a four-goal deficit in order to qualify for the quarter-finals. Other example include FC Barcelona (5–1, 6–4 on aggregate) against Chelsea F.C. in the UEFA Champions League quarterfinal on April 18, 2000 at Camp Nou. Barcelona entered the second leg with a 3-1 deficit against Chelsea, Rivaldo and Luís Figo both scored in the first half to tie the aggregate score 3-3, However in the 60th minute, Tore André Flo scored to make the aggregate score 4-3 for Chelsea, but in the 83rd minute, Dani García equalized to make the tie 4–4 on aggregate and sent the game to extra time where Rivaldo and Patrick Kluivert scored for Barcelona to complete the comeback and win the tie 6-4.

Other comebacks also include Liverpool F.C (FC Barcelona 0–4 Liverpool FC, 4–3 on aggregate) against FC Barcelona in the 2018–19 UEFA Champions League Semi-finals. With Liverpool being down 3–0 after the first game, Divock Origi and Georginio Wijnaldum came to the rescue as both netted two goals each, and an extraordinary corner kick from Trent Alexander-Arnold would give the Reds a 4–3 lead on aggregate, sending them through to the 2019 UEFA Champions League Final, which they would later win. In the other semi-final, contested between Tottenham Hotspur and Ajax, another great comeback occurred, as with Ajax having won their away leg 1–0, and winning their home leg 2–0 at half-time, Spurs needed to score three goals in the second half to win the game, where Lucas Moura scored a hat-trick that sent them to their first UEFA Champions League Final on away goals, with the winning goal coming in the 96th minute.

Real Madrid completed three successful comebacks in the 2021–22 UEFA Champions League knockout phase. In the Round of 16, Paris Saint-Germain F.C. led Real in the aggregate score 2–0 with about 30 minutes left to be played. Karim Benzema made a hat-trick in just 17 minutes to take the Spanish side to the next round. Later in the quarter-finals, after defeating Chelsea Football Club 1–3 at Stamford Bridge on the first leg with another hat-trick by Benzema, Madrid allowed three goals in the second leg at home to lose the advantage and fall behind 4–3 on aggregate. However, Rodrygo made a late goal in the 80th minute to even the aggregate, assisted by Luka Modrić, and in the subsequent extra time, Benzema scored with a header once more to help his team to reach the semi-finals. In this round, after losing 4–3 to Manchester City at the City of Manchester Stadium, Riyad Mahrez scored late in the second half of the second leg to put City 5-3 ahead and appear to secure a place in the final for City, however, Rodrygo made a double in the 90th and 91st minutes to equal the tie at 5-5 on aggregate. In extra time, Benzema successfully took a penalty in the 95th minute to put Real ahead on aggregate 6–5, allowing Madrid to reach the final, which they later won.