Chelsea F.C.–Leeds United F.C. rivalry

The rivalry between Chelsea and Leeds United is a football rivalry between London-based club Chelsea and Yorkshire-based Leeds United. The rivalry first emerged in the 1960s after a series of fiercely contested and controversial matches, when the two clubs were frequently involved in the pursuit of domestic and European honours culminating in the 1970 FA Cup final, which is regarded as one of the most physical matches in English football history.

The perceived contrast between the clubs also fuelled the rivalry, summed up as "Yorkshire grit versus flash Cockney." The rivalry between the clubs often spilled out onto the terraces: at the height of British football hooliganism in the 1970s and 1980s, Chelsea's Headhunters and Leeds' Service Crew were among the most notorious football firms and had numerous violent encounters with each other. Hooliganism has been effectively curtailed since the 1990s and the rivalry has since declined.

In the Official Chelsea Biography, Leeds were cited as one of Chelsea's major rivalries. However, Leeds' relegation from the Premier League in 2004 had effectively ended the rivalry; the clubs only met once in sixteen years afterwards. The clubs met again in the 2020–21 Premier League season, as Leeds United was promoted after winning the EFL Championship in 2019–20. The first such meeting ended in a 3–1 Chelsea victory at Stamford Bridge on 5 December 2020, and evidence of the rivalry resurfaced. In the 2003 Football Fans Census, while Leeds fans named Chelsea as their second-biggest rivals, behind Manchester United, Chelsea fans consider Arsenal to be their main rivals, followed by a rivalry with Tottenham Hotspur and Manchester United.