1903
Events
January
- January 1 – Edward VII is proclaimed Emperor of India.
- January 10 – The Aceh Sultanate was fully annexed by the Dutch forces, deposing the last sultan, marking the end of the Aceh War that have lasted for almost 30 years.
- January 19 – The first west–east transatlantic radio broadcast is made from the United States to England.
February
- February 13 – Venezuelan crisis: After agreeing to arbitration in Washington, the United Kingdom, Germany and Italy reach a settlement with Venezuela resulting in the Washington Protocols. The naval blockade that began in 1902 ends.
- February 23 – Cuba leases Guantánamo Bay to the United States "in perpetuity".
March
- March 2 – In New York City, the Martha Washington Hotel, the first hotel exclusively for women, opens.
- March 3 – The British Admiralty announces plans to build the Rosyth Dockyard as a naval base at Rosyth in Scotland.
- March 5 – The Ottoman Empire and the German Empire sign an agreement to build the Constantinople–Baghdad Railway.
- March 12 – The University of Puerto Rico is founded.
- March 13 – Having abolished the Sokoto Caliphate in West Africa, the new British administration accepts the concession of its last vizier.
- March 14 – The Hay–Herrán Treaty, granting the United States the right to build the Panama Canal, is ratified by the United States Senate. The Colombian senate later rejects the treaty.
April
- April 19–21 – The first Kishinev pogrom, beginning on Easter Day, takes place in Kishinev, capital of the Bessarabia Governorate of the Russian Empire. At least 47 Jews are killed during mob rioting encouraged by blood libel articles in the press and led by priests.
- April 26 – Atlético Madrid is founded as a professional association football club in Spain.
- April 29
- *The 30-million-m3 Frank Slide rockslide kills 70–90 in Frank, Alberta.
- *The 7.0 Manzikert earthquake affects eastern Turkey, leaving 3,500 dead.
May
- May 4 – Macedonian Bulgarian revolutionary Gotse Delchev is killed in a skirmish with the Ottoman army.
- May 18 – The port of Burgas, Bulgaria opens.
- May 24 – The Paris–Madrid race for automobiles begins, during which at least eight people are killed; the French government stops the event at Bordeaux and impounds all of the competitors' cars.
- May 26 – Românul de la Pind, the longest-running newspaper by and about Aromanians until World War II, is founded.
June
- June 11 – King Alexander Obrenović and Queen Draga of Serbia are assassinated in Belgrade by the Black Hand organization.
- June 14 – The town of Heppner, Oregon is nearly destroyed by a cloud burst that results in a flash flood that kills about 238 people.
- June 16 – The Ford Motor Company is founded.
- June 27 – American socialite Aida de Acosta, 19, becomes the first woman to fly a powered aircraft solo when she pilots Santos-Dumont's motorized dirigible, "No. 9", from Paris to Château de Bagatelle in France.
July
- July 1–19 – The first Tour de France is held; Maurice Garin wins it.
- July 7 – Britain take over the Fulani Empire.
- July 29 – United States Cartridge Company explosion: The explosion of two explosives storage magazines destroys 70 homes, killing 22 residents of Tewksbury, Massachusetts.
- July 30–August 23 – The Second Congress of the All-Russian Social Democratic Labour Party is held in exile in Brussels, transferring to London.
August
- August 2 – The Ilinden–Preobrazhenie Uprising, organized by the Secret Macedonian-Adrianople Revolutionary Organization, breaks out in the Ottoman provinces of Macedonia and Adrianople.
- August 3 – The Kruševo Republic is proclaimed in Ottoman Macedonia; it is crushed 10 days later.
- August 4 – Pope Pius X succeeds Pope Leo XIII as the 257th pope.
- August 10 – The Paris Métro train fire at Couronnes results in 84 deaths.
- September – Texas State University in San Marcos, Texas opens as Southwest Texas Normal School.
- September 11 – The first stock-car event is held at the Milwaukee Mile.
- September 15 – Grêmio FBPA is founded in Porto Alegre, Brazil.
- September 27 – The Wreck of the Old 97 Fast Mail train at Stillhouse Trestle, near Danville, Virginia, kills 11 people and inspires a ballad.
October
- October 1–13 – First modern World Series: The Boston Americans defeat the Pittsburgh Pirates in eight games.
- October 10 – The Women's Social and Political Union is founded in the U.K.
November
- November 3 – Separation of Panama from Colombia: With the encouragement of the United States, Panama proclaims itself independent of Colombia.
- November 6 – The English-language South China Morning Post newspaper is first published in Hong Kong.
- November 13 – The United States recognizes the independence of Panama.
- November 17 – The Russian Social Democratic Labour Party splits into two groups: the Bolsheviks and Mensheviks.
- November 18 – The Hay–Bunau-Varilla Treaty is signed by the United States and Panama, giving the U.S. exclusive rights over the Panama Canal Zone.
- November 28 – is wrecked on a reef outside Melbourne, Australia, causing one of the world's first major oil spills.
December
- December 16 – The Taj Mahal Palace Hotel in Bombay, India opens.
- December 17 – Orville Wright flies an aircraft with a petrol engine, the Wright Flyer, at Kitty Hawk, North Carolina in the first documented and successful powered and controlled heavier-than-air flight.
- December 30 – The Iroquois Theatre fire in Chicago kills 600.
- December 31 – The National Association for Women's Suffrage is founded.
Date unknown
- The first box of Crayola crayons is made and sold for five cents. It contains eight colors; brown, red, orange, yellow, green, blue, violet and black.
- American motorcycle brand Harley-Davidson is founded in Wisconsin.
- Compression Rheostat, the predecessor of industrial automation and industrial equipment parts brand Rockwell Automation, is founded in Wisconsin.
Births
January
- January 1 – Jasimuddin, Bangladeshi poet, lyricist, composer and writer
- January 2 – Kane Tanaka, Japanese supercentenarian, oldest Japanese person ever, last surviving person born in 1903
- January 4 – Georg Elser, German carpenter and attempted assassin of Adolf Hitler
- January 6 – Maurice Abravanel, Greek-born American conductor
- January 10 – Barbara Hepworth, English sculptor
- January 11 – Alan Paton, South African author, anti-apartheid activist
- January 12 – Igor Kurchatov, Russian physicist
- January 16
- *Peter Brocco, American actor
- *William Grover-Williams, Anglo/French race car driver, war hero
- January 22 – Fritz Houtermans, Polish physicist
- January 23 – Jorge Eliécer Gaitán, Colombian politician
- January 27 – John Eccles, Australian neuropsychologist, recipient of the Nobel Prize in Physiology or Medicine
February
- February 3 – Douglas Douglas-Hamilton, 14th Duke of Hamilton, Scottish nobleman, aviation pioneer
- February 4 – Alexander Imich, Polish-born American parapsychologist, chemist
- February 6 – Claudio Arrau, Chilean-born pianist
- February 8 – Tunku Abdul Rahman, first Prime Minister of Malaysia
- February 10
- * Waldemar Hoven, German physician
- * Matthias Sindelar, Austrian footballer
- February 12 – Jorge Basadre, Peruvian historian
- February 13 – Georges Simenon, Belgian writer
- February 14 – Stuart Erwin, American actor
- February 16 – Edgar Bergen, American ventriloquist
- February 17 – Joaquín Rodríguez Ortega, Spanish bullfighter
- February 21
- * Anaïs Nin, French-born American writer
- * Raymond Queneau, French poet, novelist
- February 22
- * Morley Callaghan, Canadian writer, media personality
- * Frank Ramsey, English mathematician
- February 24 – Vladimir Bartol, Slovenian author
- February 26 – Giulio Natta, Italian chemist, Nobel Prize laureate
- February 28 – Vincente Minnelli, American stage and film director
March
- March 4
- * Dorothy Mackaill, British-born American actress
- * John Scarne, American magician, card expert
- March 6
- * Empress Nagako, Japanese consort of Emperor Hirohito
- * Józef Skoczyński, Polish Roman Catholic priest and social activist
- March 10
- * Bix Beiderbecke, American jazz musician
- * Clare Boothe Luce, American publisher, writer
- March 11
- * Ronald Syme, New Zealand-born classicist, historian
- * Lawrence Welk, American television musician, bandleader
- March 14 – Mustafa Barzani, Kurdish politician
- March 18 – Galeazzo Ciano, Italian aristocrat and diplomat
- March 19 – Wage Rudolf Supratman, Indonesian violinist
- March 20 – Edgar Buchanan, American actor
- March 21 – Frank Sargeson, New Zealand writer
- March 23 – Germán Busch, 36th President of Bolivia
- March 24
- * Adolf Butenandt, German chemist, Nobel Prize laureate
- * Malcolm Muggeridge, English journalist
- March 25
- * Binnie Barnes, English actress
- * Nahum Norbert Glatzer, Austrian-American historian and philosopher
- March 28 – Rudolf Serkin, Austrian pianist
April
- April 3 – Lola Alvarez Bravo, Mexican photographer
- April 6
- * Mickey Cochrane, American baseball player
- * Doc Edgerton, American electrical engineer
- April 9 – Gregory G. Pincus, American biologist, researcher
- April 12 – Jan Tinbergen, Dutch economist, Nobel Prize laureate
- April 15 – John Williams, English actor
- April 17
- * Gregor Piatigorsky, Russian-born American cellist
- * Morgan Taylor, American athlete
- April 19 – Eliot Ness, American Prohibition agent
- April 24 – José Antonio Primo de Rivera, Spanish politician
- April 25 – Andrey Kolmogorov, Soviet mathematician