|Centuries:||19th century – 20th century – 21st century|
|Decades:||1880s 1890s 1900s – 1910s – 1920s 1930s 1940s|
|Years:||1909 1910 1911 – 1912 – 1913 1914 1915|
- January 1 – Establishment of Republic of China.
- January 5 – Prague Party Conference
- January 6 – New Mexico is admitted as the 47th U.S. state.
- January 17 – British polar explorer Robert Falcon Scott and a team of four begin the second expedition to reach the South Pole.
- January 23 – The International Opium Convention is signed at The Hague.
- February 8 – Mexican Revolution – Military rebellion against the rule of Francisco Madero begins in Mexico City. Battles last for 10 days
- February 12 – Republic of China adopts the Gregorian calendar
- February 14 – Arizona is admitted as the 48th U.S. state.
- February 14 – In Groton, Connecticut, the first diesel-powered submarine is commissioned.
- February 18 – Francisco Madero is forced to resign – battle ends. All members of Madero's government are arrested.
- February 19 – Prizes are included in Cracker Jack candy boxes for the first time
- February 22 – Francisco Madero and Pino Suarez are shot, allegedly when they "tried to escape"
- March 1 – Albert Berry makes the first parachute jump from a moving airplane.
- March 1 – Georg Ritter von Trapp, head of the famous Austrian singing family memorialized in the musical The Sound of Music marries Agathe
- March 5 – Italian forces are the first to use airships for a military purpose by using them for reconnaissance west of Tripoli behind Turkish lines.
- March 7 – Roald Amundsen announces discovery of the South Pole
- March 7 – French aviator Henri Seimet makes the first non-stop flight from Paris to London in three hours
- March 12 – The Girl Guides (later renamed the Girl Scouts) are founded.
- March 16 – Lawrence Oates, ill member of Scott's South Pole expedition leaves the tent saying, "I am just going outside and may be some time"
- March 27 – Mayor Yukio Ozaki of Tokyo gives 3,000 cherry blossom trees to be planted in Washington, D.C. to symbolize the friendship between the two countries.
- March 30 – France establishes a protectorate over Morocco.
- April 14–15 – The R.M.S Titanic sank after hitting an iceberg in the middle of the Atlantic Ocean. Over 1500 people died.
- Alexis Carrel, French surgeon, won the 1912 Nobel Prize in Physiology or Medicine