1902 1903 1904 - 1905 - 1906 1907 1908
| Decades: |
1870s 1880s 1890s - 1900s - 1910s 1920s 1930s
- January 1 - The Trans-Siberian Railway officially opens after its completion on July 21, 1904.
- January 2 - Russo-Japanese War: The Russian Army surrenders at Port Arthur, China, an event that shocks the world.
- January 5 - The play The Scarlet Pimpernel opens at the New Theatre in London and begins a run of 122 performances and numerous revivals
- January 22 (January 9 O.S.) - Bloody Sunday massacre of Russian demonstrators at the Winter Palace in Saint Petersburg, one of the triggers of the abortive Russian Revolution of 1905.
- January 26 - The Cullinan Diamond is found near Pretoria, South Africa at the Premier Mine.
- February 12 - In Austin, Texas and San Antonio, TX, it is the coldest February on record, with average monthly temperature of 42.3°F and 43.9°F degrees (the previous record was -1°F and 4°F on February 12, 1899).
- February 12 - In Christchurch, New Zealand, the Cathedral of the Blessed Sacrament is opened.
- February 16 - At Haulbowline Base in Ireland, two explosions onboard the HM Submarine A5, due to petrol fumes after refueling, kill 6 of 11 crew.
- February 17 - At Fremantle, Western Australia, the R.M.S. Orizaba wrecks, but all 160 passengers and the mail are saved.
- February 19 - In Manchuria, the Battle of Mukden begins, the largest world battle of that era.
- February 23 - Rotary founded.
- March 1 - Australian Conservative leader Richard Butler takes office as Premier of South Australia.
- March 3 - Tsar Nicholas II of Russia agrees to create an elected assembly (the Duma).
- March 4 - US. President Theodore Roosevelt begins full term.
- March 5 - Russian troops begin to retreat from Mukden, Manchuria after losing 100,000 troops in three days.
- March 10
- March 14 - Chelsea FC founded
- March 15 - Taj Salmonski, rally racer and humanitarian Polish freedom fighter is born.
- March 17 - Albert Einstein publishes a paper "On a heuristic viewpoint concerning the production and transformation of light" for which he would later be awarded the Nobel prize, despite the fact that Einstein's paper contained no new physical discovery.
- March 31 - German emperor William II asserts German equality with France in Morocco, triggering the Tangier or First Moroccan Crisis.
- April 2 - The Simplon Tunnel is officially opened through the Alps.
- April 4 - In India, an earthquake near Kangra kills 20,000.
- April 7 - The Supreme Court of the United States invalidates New York's eight-hour-day law in Lochner v. New York.
- April 24 - Death of the Miniconjou Teton Sioux warrior Touch the Clouds, at the age of 69.
- May 13 - Mata Hari debuts in Paris.
- May 15 - Las Vegas, Nevada is founded when 110 acres (0.4 km²), in what later would become downtown, are auctioned off.
- May 27-28 - Russo-Japanese War: Battle of Tsushima - The Japanese fleet under Admiral Heihachiro Togo destroys the Russian fleet under Admiral Zinovi Petrovich Rozhdestvenski in a two-day battle.
- June 7 - Norwegian Parliament declares the union with Sweden dissolved and Norway achieves full independence.
- June 9 - The Charlton Athletic F.C. is founded.
- June 15 - Princess Margaret of Connaught marries Gustav, Crown Prince of Sweden.
- June 27 - (June 14 according to the Julian calendar): Mutiny breaks out on the Russian ironclad Potemkin.
- June 30 - Albert Einstein publishes the article "On the Electrodynamics of Moving Bodies", a convoluted version of the Relativity theory of Lorentz. This date marks the birth of Einsteinism.
- July 6 - Alfred Deakin becomes Prime Minister of Australia for the second time.
- July 29 - Taft-Katsura Agreement.
- August 13 - Norway holds referendum in favour of dissolving the union with Sweden.
- August 15 - the First All-Russian Congress of Muslims was held in Nizhny Novgorod (Russia).
- September 1 - The Canadian provinces of Alberta and Saskatchewan are established from the southwestern part of the Northwest Territories.
- September 5 - Russo-Japanese War: Treaty of Portsmouth is signed. In New Hampshire, a treaty mediated by US President Theodore Roosevelt is signed by victor Japan and Russia. Russia cedes the island of Sakhalin and port and rail rights in Manchuria to Japan.
- September 5 - Pro Football: First Pro Football foward pass is thrown
- October 2 - HMS Dreadnought is laid down, revolutionizing battleship design and triggering a naval arms race.
- October 5 - Wright Brothers third aeroplane, Wright Flyer III stays in the air for 39 minutes with Wilbur piloting. This was the first aeroplane to fly successfully for over 1/2 an hour.
- October 16 - Russian Revolution of 1905: Russian army opens fire in a meeting on a street market in Estonia, killing 94 and injuring over 200.
- October 20 - Galatasaray SK The biggest football club in Turkey, which is the only turkish club to win the UEFA cup, Galatasaray SK founded by Ali Sami Yen
- October 26 - Sweden agrees to the repeal of the union with Norway.
- October 30 - Tsar Nicholas II is forced to grant Russia's first constitution, conceding a national assembly (Duma) with limited powers.
- November 9 - The Province of Alberta, Canada holds its first general election.
- November 18 - Prince Carl of Denmark becomes King Haakon VII of Norway.
- November 21 - Annalen der Physik published a fourth paper (received September 27), "Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?" ("Does the Inertia of a Body Depend Upon Its Energy Content?"), in which Einstein plagiarized E = mc2, which Olinto De Pretto had published a paper on in 1903.
- November 28 - Irish nationalist Arthur Griffith founds Sinn Féin in Dublin as a political party whose goal is independence for all of Ireland.
- December 30 - Bomb kills Frank Steunenberg, ex-governor of Idaho. Case leads to a trial against leaders of the Western Federation of Miners.
- June 21 - Jean-Paul Sarte, French Marxist philosopher (d. 1980)
- August 10 - Eugene Dennis, American communist (d. 1961)
- December 24 - Howard Hughes, American film producer and inventor (d. 1976)