This timeline of women in warfare and the military (1900–1939) deals with the role of women in the military around the world from 1900 through 1939. By the end of the 19th century, women in some countries were starting to serve in limited roles in various branches of the military. This trend continued through the following decades. By the beginning of World War II, the number of roles played by women was growing.
1908: The United States establishes the Navy Nurse Corps on 13 May. The Corps remains all-female until 1965. The first 20 nurses (the first women in the Navy) report to Washington, D.C. in October 1908. By the end of World War I, their numbers increase to 1,386. During the war, the nurses serve on transport duty overseas in England, Ireland, and Scotland.
1912: Rayna Kasabova is the first woman in history to participate in a military flight, flying as an observer on combat missions during the Balkan Wars. She carries out a number of sorties, including dropping propaganda materials and bombs on Ottoman positions during the siege of Adrianople.
1913: U.S. Navy nurses (all women) serve on the transports USS Mayflower and USS Dolphin.
Australia: More than 3,000 Australian civilian nurses volunteer for active service.
Britain: The British form the Women's Army Auxiliary Corps in 1917; the Corps is renamed the Queen Mary's Army Auxiliary Corps in 1918. Members of this corps serve as clerical staff, cooks and medical personnel. It is disbanded in September 1921. Also in 1917, the British form the Women's Royal Naval Service as a branch of the Royal Navy. Members of this corps serve as clerks, cooks, electricians and air mechanics. The British disband the unit in 1919.
Canada: Over 2,800 women serve in the Royal Canadian Army Medical Corps during the war. Women also receive training in small arms, first aid and vehicle maintenance in anticipation of being used as home guards.
New Zealand: Nurses in the New Zealand Army Nursing Service serve on hospital ships and in hospitals at the front in France.
Romania: During the 1916 battle in the Jiu Valley, Ecaterina Teodoroiu transfers from the Romanian Army's all-female nurse corps to the Reconnaissance Corps. She is taken prisoner while serving as a scout, but escapes after killing several German soldiers. In November she is wounded and hospitalized, but returns to the front; she is decorated, promoted to Sublocotenent (second lieutenant) and given the command of a 25-man platoon. For her valor she is awarded the Military Virtue Medal, First Class. On September 3, 1917 (August 22 Old Style) she is killed in the Battle of Mărăşeşti (in Vrancea County) after being hit in the chest by German machine-gun fire. According to some accounts, her last words before dying were "Forward, men, I'm still with you!"
Russia: Russia fields 15 formations of female battalions for several months in 1917; two (the 1st Russian Women's Battalion of Death and the Perm Battalion) are deployed to the front. By the end of the year, all battalions are dissolved.
United States: During America's involvement from 1917–1918, 21,480 U.S. Army nurses (military nurses are all women) serve in military hospitals in the United States and overseas. Eighteen African-American Army nurses serve at home, caring for German prisoners of war and African-American soldiers. The first female members of the military killed in the line of duty are Edith Ayres and Helen Wood, who die on May 20, 1917 at Base Hospital #12 aboard the USS Mongolia en route to France. The U.S. Army recruits and trains 233 female bilingual telephone operators to work at switchboards near the front in France, and sends 50 skilled stenographers to France to work with the Quartermaster Corps. On 19 March 1917, the U.S. Navy authorizes the enlistment of women. Designated as "Yeoman (F)," they unofficially become known as "Yeomanettes.” The U.S. Navy enlists 11,880 women as Yeomen (F), to serve in shore billets and release sailors for sea duty. On 21 March 1917, YNC Loretta Perfectus Walsh becomes the first female Chief Petty Officer in the U.S. Navy. More than 1,476 U.S. Navy nurses serve in military hospitals. The U.S. Marine Corps enlists 305 female Marine Reservists (F) to "free men to fight" by filling positions (such as clerks and telephone operators) on the home front. In 1918, Pvt. Opha Mae Johnson becomes the first woman to enlist in the U.S. Marine Corps Reserve. More than 400 U.S. military nurses die in the line of duty during World War I, the vast majority from the pandemic Spanish Flu. In 1918, twin sisters Genevieve and Lucille Baker of the Naval Coastal Defense Reserve become the first uniformed women to serve in the U.S. Coast Guard. At the time of the armistice on November 11, 1918 there are 11,275 Yeomanettes in naval service, with some 300 female Marines in the Marine Corps. The women, "no longer needed", are asked to resign. The final pass in review down Pennsylvania Avenue is in July. The U.S. Naval Reserve Act of 1916 permits the enlistment of qualified "persons" for service. Secretary of the Navy Josephus Daniels asks, "Is there any law that says a Yeoman must be a man?" and is told there is not.
1920: During the Turkish War of Independence, Kara Fatma and her group conducts operations against British, Armenian, French, Italian and Greek soldiers, especially targeting those who rape young girls. A provision of the Army Reorganization Act grants U.S. military nurses the status of officers, with "relative rank" from second lieutenant to major (but not full rights and privileges). U.S. Nurses (all women) serve aboard the first U.S. ship built as a floating hospital, the USS Relief (AH-1).
1924: Lottorna, the Swedish Women's Voluntary Defence Service, is founded.