The first IWD was observed on 19 March 1911 in Germany following a declaration by the Socialist Party of America. Among other relevant historic events, it came to commemorate the 1911 Triangle Shirtwaist Factory fire. The idea of having an international women's day was first put forward at the turn of the 20th century amid rapid world industrialization and economic expansion that led to protests over working conditions.

In 1910 the first international women's conference was held in Copenhagen (in the labour-movement building located at Jagtvej 69, which until recently housed Ungdomshuset) by the Second International and an 'International Women's Day' was established, which was submitted by the important German Socialist Clara Zetkin, although no date was specified. The following year, 1911, IWD was marked by over a million people in Austria, Denmark, Germany and Switzerland, on March 19. However, soon thereafter, on March 25, the Triangle Shirtwaist Factory fire in New York City killed over 140 garment workers. A lack of safety measures was blamed for the high death toll. Furthermore, on the eve of World War I, women across Europe held peace rallies on 8 March 1913. In the West, International Women's Day was commemorated during the 1910s and 1920s, but dwindled. It was revived by the rise of feminism in the 1960s.

Demonstrations marking International Women's Day in Russia proved to be the first stage of the Russian Revolution of 1917.

Following the October Revolution, the Bolshevik Alexandra Kollontai persuaded Lenin to make it an official holiday in the Soviet Union, and it was established, but was a working day until 1965. On May 8, 1965 by the decree of the USSR Presidium of the Supreme Soviet International Women's Day was declared as a non working day in the USSR "in commemoration of the outstanding merits of Soviet women in communistic construction, in the defense of their Fatherland during the Great Patriotic War, in their heroism and selflessness at the front and in the rear, and also marking the great contribution of women to strengthening friendship between peoples, and the struggle for peace. But still, women's day must be celebrated as are other holidays."

The day is an official holiday in Afghanistan, Armenia, Azerbaijan, Belarus, Burkina Faso, Cambodia, China (for women only), Croatia, Cuba, Georgia, Guinea-Bissau, Eritrea, Kazakhstan, Kyrgyzstan, Laos, Madagascar (for women only), Moldova, Mongolia,Montenegro, Nepal (for women only), Russia, Serbia, Tajikistan, Turkmenistan, Uganda, Ukraine, Uzbekistan, Vietnam, and Zambia.

In some countries, such as Cameroon or Romania, the day is not a public holiday, but is widely observed nonetheless.

In 1975, which had been designated as International Women’s Year, the United Nations gave official sanction to and began sponsoring International Women's Day.

The 2005 Congress (conference) of the British Trades Union Congress overwhelmingly approved a resolution calling for IWD to be designated a public holiday in the United Kingdom.