Ernst Meyer (10 July 1887, Prostken – 2 February 1930, Potsdam) was a German Communist political activist and politician. He is best remembered as a founding member and top leader of the Communist Party of Germany and as the leader of that party's fraction in the Prussian Landtag. A political opponent of Ernst Thälmann, Meyer was moved out of the top party leadership after 1928, not long before his death of tuberculosis-related pneumonia at the age of 43.
Ernst Meyer was born in 1887 in Prostken, East Prussia.
Meyer studied economics and philosophy at the University of Königsberg, from which he received a PhD in 1910.
Meyer joined the Social Democratic Party of Germany (SPD) in 1908, while he was still a student in college, beginning to write almost immediately for Vorwärts (Forward), the SPD's official daily newspaper. In 1911 Meyer was promoted to the position of the economics editor of 'Vorwärts.
At the time of World War I, Meyer took his place on the extreme left of the SPD, along with Rosa Luxemburg, Karl Liebknecht, Franz Mehring, and Clara Zetkin. He was a close political friend of Leo Jogiches and participated in the issuance of the letters and leaflets of the Spartakusbund (Spartacus League). Meyer remained the only Spartakan on the editorial board of Vorwarts and he attempted to resist efforts by the majority of the editorial board to support German efforts in the war. This discordant position made Meyer a target of the SDP's right wing and on April 15, 1915, he was removed from his position on the paper's editorial board.