It's generally agreed that International Women's Day grew from labor movements of the late 1800s and early 1900s. In particular, garment workers were fighting for reduced hours and safer working conditions. On March 8, 1857, protesters were attacked by police, and the first women's labor union grew from this movement. A similar protest was held on March 8, 1908, and helped inspire America's National Women's Day in February 1909.

In 1910 the Socialist International met in Denmark, and an International Conference of Socialist Women was held before the main conference. A German delegate called Clara Zetkin proposed a holiday honoring the women striking in the United States, which was approved by delegates. Known as the International Working Women's Day, it was celebrated on March 19, 1911, and rallies were held in Denmark, Switzerland, Germany, and Austria. At the time only Australia, New Zealand, Sweden, Norway, and Finland had granted women the right to vote.

Just a week after the first International Working Women's Day was celebrated in Europe, tragedy struck in New York. The Triangle Shirtwaist Factory Fire occurred on March 25, 1911, killing 146 workers who were mostly young immigrant women and girls. Most of the deaths were caused by locked doors in the factory and neglected safety features, making them completely preventable. The fire brought attention to the conditions inside factories and led to workplace reform. One eyewitness, Frances Perkins, was inspired to become a worker's rights activist and later became President Roosevelt's Secretary of Labor and the first woman appointed to the U.S. Cabinet.

In Russia, International Women's Day was first celebrated in 1913 and commemorations continued in following years. On February 23, 1917, women in Russia marched for bread and peace. They demanded an end to World War I, food shortages and czarism. Textile workers left work and asked for support from others, leading to a mass strike and sparking the February Revolution. Seven days later the Tsar abdicated, and the provisional government gave women the right to vote. Revolutionary leader Leon Trotsky later said, "...meetings and actions were foreseen. But we did not imagine that this 'Women's Day' would inaugurate the revolution."

For many years, International Women's Day was largely a communist holiday. It was declared an official holiday in the Soviet Union following the revolution and is still a national, non-work day in many current and former communist countries, including Armenia, Cuba, and Vietnam. In China and Madagascar, the day is a public holiday for women only.

In the 1960s, International Women's Day was renamed "Women's International Day of Struggle" by women in Europe. Second-wave feminism moved the focus of the women's movement away from legal rights such as suffrage to the issues of sexuality, family, injustices in society and the workplace, reproductive rights, harassment, and violence. As International Women's Day was taken up as a day of action by women, protests in the 1970s and 1980s often centered around subsidized child care, equal pay and an end to domestic violence.

The United Nations had an emphasis on women's rights from its conception. The UN Charter of 1945 was the first international agreement to recognize equality between men and women. The UN declared 1975 as the International Women's Year and the organization has celebrated International Women's Day on March 8 ever since. UN member nations at the time were invited to declare the date a day of women's rights and world peace.

Women's History Month is held in March to correspond with International Women's Day. Countries including the United States, Australia, Canada, Russia, and Ukraine take the opportunity to highlight women's contributions to history. Often the month has a theme to provide focus to particular areas of history, such as education, art, women in public service and women who fight discrimination. The month grew from Women's History Week, which was first formally celebrated in 1980 following a proclamation by President Carter.

Over the years, International Women's Day has become associated with protesting for peace. In 1914, with the threat of war in Europe, women rallied against war and in solidarity with women in other countries at risk of war. During the 1960s many women involved in the feminist movement were also working against the Vietnam War. As the U.S. and other countries entered conflicts in the Middle-East, some International Women's Day rallies were organized around ending war there and throughout the world.