See also: 1937 in sports, other events of 1938, 1939 in sports and the list of 'years in sports'.

Baseball

• World Series: New York Yankees defeat the Chicago Cubs, 4-0.
• Hall of Fame election: Continuing toward the goal of 10 initial inductees at the 1939 opening of the Hall, voters select Grover Cleveland Alexander. A special committee selects organizer Alexander Cartwright and promoter Henry Chadwick; selections of 19th century players are again postponed.

Boxing

• American boxer Henry Armstrong simultaneously holds the featherweight, welterweight & lightweight world titles.

American Football

• New York Giants 23-17 Green Bay Packers for the NFL title.

Football (Australian Rules)

• Victorian Football League
  • Carlton wins the 42nd VFL Premiership (Carlton 15.10 (100) d Collingwood 13.7 (85))
  • Brownlow Medal awarded to Dick Reynolds (Essendon)

Football (Soccer)

• June - Italy wins Football World Cup in France

Snooker

• World Snooker Championship: Joe Davis beats Sidney Smith 37-24

Tennis

• American, Don Budge becomes the first male tennis player to complete the Grand Slam in tennis of all 4 Championships.

Events

• February - British Empire Games held in Sydney, Australia
• March 3 - Glenn Cunningham breaks the world record for the indoor mile run by completing the distance in 4 minutes, 4.4 seconds.
• In what was billed as the "Match of the Century", Seabiscuit defeated the United States Triple Crown of Thoroughbred Racing champion, War Admiral.

Births

• October 7 – Anny Haydon, future tennis champion

Deaths

• January 27 - Bernd Rosemeyer, race car driver
• July 4 - Suzanne Lenglen, tennis great