- May 1 British coal miners go on strike
- May 1 Baseball Hall of Fame pitcher Satchel Paige (19) debuts in the Negro Southern League for Chattanooga
- May 2 US military intervenes in Nicaragua
- May 3 British General Strike: Trade Union Congress calls for a general strike 1 minute to midnight to support striking coal miners
- May 3 Pulitzer prize awarded to Sinclair Lewis (Arrowsmith)
- May 3 US Marines land in Nicaragua (9 months after leaving), stay until 1933
- May 5 Geldrop soccer team forms
- May 5 Sinclair Lewis refuses his Pulitzer Prize for "Arrowsmith"
- May 8 A Philip Randolph organizes Brotherhood of Sleeping Car Porters
- May 8 Fire breaks out in Fenway Park, home of Boston Red Socks baseball team
Event of Interest
May 9 1st flight over the North Pole claimed by Richard E. Byrd and co-pilot Floyd Bennett. Later discovery of Byrd's diary suggests they may have turned back 150 miles short of the pole due to an oil leak.
Richard E. Byrd
Event of Interest
May 12 Airship Norge is the first vessel to fly over North Pole, lead by Roald Amundsen and piloted by Umberto Nobile
Roald Amundsen
Music Premiere
May 12 Dmitri Shostakovich's 1st Symphony premieres in Leningrad
Dmitri Shostakovich
- May 12 General Józef Piłsudski returns to power in Poland after coup d'état against the Witos regime
- May 12 Hans Luther resigns for 2nd time as German Chancellor after no-confidence vote against his minority government
- May 12 British General Strike ends after 9 days, coal mine workers stay on strike
- May 15 52nd Kentucky Derby: Albert Johnson on Bubbling Over wins in 2:03.8
Event of Interest
May 17 Chiang Kai-shek is made supreme warlord in Canton
Chiang Kai-shek
- May 17 Wilhelm Marx succeeds Hans Luther as Chancellor of Germany
- May 18 Evangelist Aimee Semple McPherson vanishes in Venice, California She shows up a month later saying she's been kidnapped
- May 19 French air force bombs Damascus Syria
- May 20 Belgian government of Jaspar takes power
- May 20 Congress passes Air Commerce Act, licensing of pilots & planes
- May 20 Railway Labor Act became law in USA
Event of Interest
May 20 Thomas Edison says Americans prefer silent movies over talkies
Thomas Edison
- May 21 White Sox Earl Sheely hits a record 6th consecutive double
- May 22 "Five Foot Two, Eyes of Blue" by Gene Austin hits #1
- May 22 Chiang Kai-shek replaces communists in Guomindang China
- May 22 Dutch Communist Party expels David Wijnkoop
- May 23 Hack Wilson is 1st to hit a home run off Wrigley Field scoreboard
- May 23 Lebanese constitution forms under French mandate
World Record
May 24 Paavo Nurmi runs world record 3000 m (8:25.4)
Paavo Nurmi
- May 25 Sholom Schwartzbard assassinates Symon Petliura, the head of the Paris-based government-in-exile of Ukrainian People's Republic
- May 26 Lebanon adopts constitution
- May 28 Military coup by General Manuel Gomes da Costa in Portugal
- May 28 US Customs Court created by congress
- May 31 Portuguese president Bernardino Machedo resigns after coup
- May 31 Sesquicentennial Exposition opens in Philadelphia
- May 31 Indianapolis 500: Frank Lockhart wins in 5:12:48.768 (154.343 km/h)