1948 in sports

• Michigan Wolverines – college football national championship
• Cleveland Browns defeated the Buffalo Bills 49–7 in the All-America Football Conference championship game.
• Philadelphia Eagles defeated the Chicago Cardinals 7–0 in the National Football League championship game. The game at Shibe Park was played in a blizzard.

Colombia

• Liga Aguila, a premier football league of Colombia, first officially game held on August 15.

Egypt

• A first Egyptian Premier League, officially game held in October 22.

England

• First Division – Arsenal win the 1947–48 title.
• FA Cup – Manchester United beat Blackpool 4–2.

Start of the 50 km walk at the London Olympics

33 athletics events were contested at the Olympic Games in London, including debuts for the men's 10 km walk; and the women's 200 metres, long jump and shot put. Fanny Blankers-Koen of the Netherlands captured four gold medals.

Victorian Football League

• Melbourne wins the 52nd VFL Premiership, drawing the 1948 VFL Grand Final with Essendon 10.9 (69) to 7.27 (69), and winning the replay 13.11 (89) to Essendon's 7.8 (50)
• Brownlow Medal awarded to Bill Morris (Richmond)

South Australian National Football League

• 2 October – Norwood wins its twenty-first SANFL premiership, defeating West Torrens 15.16 (106) to 7.7 (49)
• Magarey Medal awarded to Ron Phillips (North Adelaide)

Western Australian National Football League

• 9 October – South Fremantle wins its fourth premiership and second in succession, defeating West Perth 13.9 (87) to 9.9 (63)
• Sandover Medal awarded to Merv McIntosh (Perth)

• January 29 – Commissioner Happy Chandler fines the Yankees, Cubs, and Phillies $500 each for signing high school players.
• February 27 – Hall of Fame election – voters select the recently deceased Herb Pennock, and Pie Traynor, as the newest inductees; Traynor is the first third baseman elected by the writers in 9 elections.
• August 16 – death of Babe Ruth
• World Series – Cleveland Indians defeat Boston Braves, 4 games to 2.
• Negro World Series – Homestead Grays defeat the Birmingham Black Barons, 4 games to 1.
• College World Series - University of Southern California defeat Yale in the 2nd 2 games to 1

NCAA Basketball Championship

• Kentucky beat Baylor 58–42

BAA (NBA) Finals

• Baltimore Bullets win four games to two over the Philadelphia Warriors

NBL Championship

• Minneapolis Lakers win three games to one over the Rochester Royals

France

• ASVEL Basket was founded in Villeurbanne, Metropolis of Lyon.

Spain

• CB Estudiantes was founded in Goya area, Madrid.

• June 25 – At New York's Yankee Stadium – Joe Louis knocked out Jersey Joe Walcott in the 11th round to retain his heavyweight title for the 25th time. Shortly after the bout, Louis announced his retirement from boxing.

• Olympic Games (men's competition) in London, Great Britain
  • Gold: India

• World Figure Skating Championships
  • Men's champion: Dick Button, United States
  • Ladies' champion: Barbara Ann Scott, Canada
  • Pair skating champions: Micheline Lannoy & Pierre Baugniet, Belgium

Men's professional

• Masters Tournament – Claude Harmon
• PGA Championship – Ben Hogan
• U.S. Open – Ben Hogan
• British Open – Henry Cotton

Men's amateur

• British Amateur – Frank Stranahan
• U.S. Amateur – Willie Turnesa

Women's professional

• Women's Western Open – Patty Berg
• U.S. Women's Open – Babe Zaharias
• Titleholders Championship – Patty Berg

• NCAA Men's Ice Hockey Championship – Michigan Wolverines defeat Dartmouth College Big Green 8-4 in Colorado Springs, Colorado to win the first official NCAA championship
• Stanley Cup – Toronto Maple Leafs beat Detroit Red Wings in 4 straight games to win their 5th Stanley Cup title.

• Citation becomes the 8th horse to win the US Triple Crown
• Shiela's Cottage becomes the first mare to win the Grand National since 1902 and only the twelfth since the race's inception

Steeplechases

• Cheltenham Gold Cup – Cottage Rake
• Grand National – Sheila's Cottage

Hurdle races

• Champion Hurdle – National Spirit

Flat races

• Australia – Melbourne Cup won by Rimfire (horse)
• Canada – Queen's Plate won by Last Mark
• France – Prix de l'Arc de Triomphe won by Migoli
• Ireland – Irish Derby Stakes won by Nathoo
• English Triple Crown Races:
  1. 2,000 Guineas Stakes – My Babu
  2. The Derby – My Love
  3. St. Leger Stakes – Black Tarquin
• United States Triple Crown Races:
  1. Kentucky Derby – Citation
  2. Preakness Stakes – Citation
  3. Belmont Stakes – Citation

• 1948 Summer Olympics takes place in London, United Kingdom
  • United States wins the most medals (84) and the most gold medals (38).
• 1948 Winter Olympics takes place in St. Moritz, Switzerland
  • Norway and Sweden both win the most medals (10 each), and the most gold medals (4 each).

• First CQ World Wide DX Contest held in October and November. This annual event would go on to become the radio contest with the largest participation worldwide.

The Boat Race

• 27 March — Cambridge wins the 94th Oxford and Cambridge Boat Race

Australia

• 1948 NSWRFL season

England

• 1947–48 Northern Rugby Football League season/1948–49 Northern Rugby Football League season

Five Nations Championship

• 54th Five Nations Championship series is won by Ireland who complete the Grand Slam, their last for 61 years.

• World Snooker Championship – Fred Davis beats Walter Donaldson 84-61.

Speed Skating World Championships

• Men's All-round Champion – Odd Lundberg (Norway)
• Women's All-round Champion – Maria Isakova (USSR)

1948 Winter Olympics (Men)

• 500m – gold medal: Finn Helgesen (Norway)
• 1500m – gold medal: Sverre Farstad (Norway)
• 5000m – gold medal: Reidar Liaklev (Norway)
• 10000m – gold medal: Åke Seyffarth (Sweden)

1948 Winter Olympics (Women)

• not contested

Australia

• Australian Men's Singles Championship – Adrian Quist (Australia) defeats John Bromwich (Australia) 6–4, 3–6, 6–3, 2–6, 6–3
• Australian Women's Singles Championship – Nancye Wynne Bolton (Australia) defeats Marie Toomey (Australia) 6–3, 6–1

England

• Wimbledon Men's Singles Championship – Bob Falkenburg (USA) defeats John Bromwich (Australia) 7–5, 0–6, 6–2, 3–6, 7–5
• Wimbledon Women's Singles Championship – Louise Brough Clapp (USA) defeats Doris Hart (USA) 6–3, 8–6

France

• French Men's Singles Championship –
• French Women's Singles Championship –

USA

• American Men's Singles Championship –
• American Women's Singles Championship –

Davis Cup

• 1948 Davis Cup –  United States 5–0  Australia at West Side Tennis Club (grass) New York City, United States

• Associated Press Male Athlete of the Year – Lou Boudreau, Major League Baseball
• Associated Press Female Athlete of the Year – Fanny Blankers-Koen, Track and field