The Estonian Social Democratic Workers' Party (Estonian: Eesti Sotsiaaldemokraatiline Tööliste Partei) was a political party in Estonia between 1917 and 1925. The leaders of the party, founded on platforms of patriotism, Estonian independence, and social justice, made a major contribution to the drafting of the first (1920) Constitution of Estonia.

This article needs additional citations for verification. (April 2019)

You can help expand this article with text translated from the corresponding article in Estonian. (July 2023) Click [show] for important translation instructions. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article. You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Estonian Wikipedia article at [[:et:Eesti Sotsiaaldemokraatlik Tööliste Partei]]; see its history for attribution. You may also add the template {{Translated|et|Eesti Sotsiaaldemokraatlik Tööliste Partei}} to the talk page. For more guidance, see Wikipedia:Translation.

Social democracy in Estonia was born at the beginning of the 20th century. Estonian social democracy was influenced by western European ideas of social democracy as well as by Russian ideals. During the Russian Revolution of 1905 social democratic ideas spread and Estonian social democrats formed their party in the summer of 1905 in Tartu.

At this time, the party was named the Estonian Social Democratic Workers Unity (Eesti Sotsiaaldemokraatlik Tööliste Ühendus). The social democrats were the most persecuted party during the czarist era. Their newspapers were closed, their politicians were forced to emigrate (Peeter Speek and Mihkel Martna) or prosecute in underground^{[clarification needed]} (August Rei).

In 1917, when parties were again allowed, social democrats formed the Estonian Social Democratic Association (Eesti Sotsiaaldemokraatlik Ühendus). Their views were patriotic and they fought for Estonian independence and social justice. In 1919, they changed their name to the Estonian Social Democratic Workers Party (Eesti Sotsiaaldemokraatlik Tööliste Partei) and won the Constituent Assembly elections with 41 of the 120 seats. In the first parliamentary elections the following year the party was reduced to third place, before emerging as the second-largest party in the 1923 elections.

In 1925, the party merged with the Estonian Independent Socialist Workers' Party to form the Estonian Socialist Workers' Party.^[1] In 1990, the Estonian Socialist Party's Foreign Association merged into the newly formed Estonian Social Democratic Party.