- May 5 Charles "Chief" Bender, American Baseball HOF pitcher (only indigenous American in BHOF; World Series 1910, 11, 13; no-hitter 1910; Philadelphia A's), born in Crow Wing County, Minnesota (d. 1954)
- May 5 Léopold Samuel, Belgian composer, born in Brussels, Belgium (d. 1975)
- May 5 Petar Konjović, Serbian composer, born in Čurug, Serbia (d. 1970)
- May 5 Archibald Wavell, 1st Earl Wavell, British general, born in Colchester, Essex, England (d. 1950)
- May 6 José Ortega y Gasset, Spanish philosopher and author (The Revolt of the Masses), born in Madrid, Spain (d. 1955)
- May 7 Gino Roncaglia, Italian composer, born in Modena, Italy (d. 1968)
- May 7 Martin Albertz, German theologist (Jesus Christ's Church) and resistance fighter against the Nazi regime, born in Halle (Saale), Germany (d. 1956)
- May 13 Henk Sneevliet, Dutch Communist, editor (Spartacus) and WWII resistance fighter, born in Rotterdam, Netherlands (d. 1942)
- May 13 Georgios Papanicolaou, Greek-American doctor, cytopathologist, and inventor of the Pap smear, born in Kymi, Greece (d. 1962)
- May 14 Jan Olieslagers, Belgian aviation pioneer (Antwerp Devil)
- May 14 Julian Eltinge [Dalton], American vaudeville, Broadway, and silent film female impersonator star (The Crinoline Girl), born in Newtownville, Massachusetts (d. 1941)
- May 15 Stanley Marchant, English composer, born in London (d. 1949)
- May 18 Walter Gropius, German architect (founder of the Bauhaus school), born in Berlin, Germany (d. 1969)
- May 19 Henricus WJM Keuls, Dutch lawyer/poet (Dancing Lamp)
- May 20 Paul Arntzenius, Dutch painter, graphic artist and etcher, born in The Hague, Netherlands (d. 1965)
- May 20 Faisal I of Iraq, King of the Arab Kingdom of Syria (1920–1933) & King of Iraq (1921–1933), born in Mecca, Saudi Arabia (d. 1933)
Douglas Fairbanks
May 23 Douglas Fairbanks, American actor (The Mark of Zorro, 3 Musketeers, Robin Hood), born in Denver, Colorado (d. 1939)
- May 25 Elsa Maxwell, American writer (Jack Paar Show), born in Keokuk, Iowa (d. 1963)
- May 26 Mamie Smith, American vaudeville singer, dancer and actress (Crazy Blues), born in Cincinnati, Ohio (d. 1946)
- May 28 George Dyson, British organist and composer (The Canterbury Pilgrims), born in Halifax, Yorkshire, England (d. 1964)
- May 28 Luigi Perrachio, Italian composer, born in Turin, Italy (d. 1966)
- May 28 Vinayak Damodar Savarkar, Indian independence activist and writer (The Indian War of Independence), born in Bhagur, India (d. 1966)
- May 28 Clough Williams-Ellis, British architect known chiefly as the creator of the Italianate village of Portmeirion in North Wales, born in Gayton, Northamptonshire, England (d. 1978)
- May 29 William Beatton Moonie, Scottish composer (The Weird of Colbar; Echoes of Perthshire), born in Stobo, Pebbleshire (d. 1961)
- May 30 Riccardo Zandonai, Italian composer, born in Borgo Sacco, Rovereto, Austria-Hungary (d. 1944)
- May 31 Lauri Kristian Relander, 2nd President of Finland (1925-31), born in Kurkijoki, Finland (d. 1942)