1884 in sports describes the year's events in world sport.
- Amos Alonzo Stagg enters Yale University as a divinity student and, a natural athlete, joins the university's football team.
- 25 October — Yale Bulldogs defeat Dartmouth 113–0. This is the first college football game where one team scores over 100 points and also the first time one team scores over 100 points while the opposing team scores zero.
- 29 October — The next week, the Princeton Tigers outscore the Lafayette Leopards by 140–0.
- FA Cup final – Blackburn Rovers 2–1 Queen's Park (Glasgow) at The Oval. Blackburn Rovers is the first extant club to win the FA Cup.
- Everton moves as tenant to Anfield, a newly enclosed ground off Anfield Road, Liverpool.
- Derby County founded by Derbyshire CCC to provide a winter activity for players and supporters.
- Leicester City founded as Leicester Fosse.
- Inauguration of the National League v. American Association fixture, sometimes called the "Original World Series" – Providence Grays (NL) defeats New York Metropolitans (AA) 3 games to nil.
- Ned Williamson hits 27 home runs for the Chicago White Stockings, establishing a record that will last for 35 years. He nearly doubles the record of 14 set the season before by Harry Stovey.
- Moses Fleetwood Walker becomes the first black American major league baseball player when he makes his American Association league debut for the Toledo Blue Stockings.
- The first of the modern World titles is recognised with Jack (Nonpareil) Dempsey as the original World Middleweight Champion. The weight limit for middleweights at this time is 154 pounds. Dempsey will hold the title until 1891.
- American heavyweight champion John L. Sullivan faces a number of challengers but none of them last more than four rounds. Sullivan is very active on the exhibition circuit.
Lineal world champions
- The Canadian Rugby Football Union, forerunner of the Canadian Football League, is established.
- An Australian team tours England but loses the three-match Test series 1–0 with two matches drawn.
- Derbyshire suffer the ignominy of a perfectly bad season losing all ten of their county games
- In stark contrast Nottinghamshire come closer to an absolutely perfect season than any county side since, winning nine games and being three wickets shy of victory in their tenth
- Champion County – Nottinghamshire
- Most runs – Lord Harris 1,417 @ 33.73 (HS 112*)
- Most wickets – Fred Spofforth 207 @ 12.82 (BB 8–62)
- Grand National – Voluptuary
- 1,000 Guineas Stakes – Busybody
- 2,000 Guineas Stakes – Scot Free
- The Derby – dead heat between Harvester and St. Gatien
- The Oaks – Busybody
- St. Leger Stakes – The Lambkin
- Queen's Plate – Williams
The Boat Race
Home Nations Championship
- The 1884 New Zealand rugby union tour of New South Wales is the inaugural overseas tour by the New Zealand team
- Inaugural women's singles championship at Wimbledon
- Wimbledon Men's Singles Championship – William Renshaw (GB) defeats Herbert Lawford (GB) 6–0 6–4 9–7
- Wimbledon Women's Singles Championship – Maud Watson (GB) defeats Lillian Watson (GB) 6–8 6–3 6–3
- American Men's Singles Championship – Richard D. Sears (USA) defeats Howard A. Taylor (USA) 6–0 1–6 6–0 6–2
- DeLassus, David. "Yale Yearly Results (1880–1884)". College Football Data Warehouse. Archived from the original on February 13, 2010. Retrieved April 4, 2011.
- DeLassus, David. "Princeton Yearly Results (1880–1884)". College Football Data Warehouse. Archived from the original on October 21, 2012. Retrieved April 4, 2011.
- "Scottish Cup Past Winners | Scottish Cup | Scottish FA". www.scottishfa.co.uk. Retrieved 5 February 2021.
- Cyber Boxing Zone – Lineal Middleweight Champions. Retrieved on 6 June 2009. Archived 2009-06-08.
- Cyber Boxing Zone – John L Sullivan. Retrieved on 12 November 2009.
- "Cyber Boxing Zone". Archived from the original on 2009-06-14. Retrieved 2009-06-17.
- A semi-official seasonal title proclaimed by media consensus prior to December 1889 when the official County Championship is constituted.
- "Epsom Derby | History, Winners, & Facts | Britannica". www.britannica.com. Retrieved 29 December 2021.