Otto Franklin Branstetter (1877-1924) was an American socialist official. Branstetter served as executive secretary of National Executive Committee of the Socialist Party of America from 1919 until shortly before his death in 1924.
In 1921, Branstetter was a prominent founding member of the secular Jewish Yiddish-oriented political organization, the Jewish Socialist Verband. In 1921, Branstetter was a lead organizer against the communist-affiliated left wing within the Socialist Party when he introduced a resolution that called for the expulsion of SPA members who supported the Communist International (comintern). On February 1, 1924, Branstetter submitted his resignation to the National Executive Committee, calling himself tired and worn out,”. He was replaced by his assistant, Bertha Hale White.
Otto and his wife, Winnie Branstetter, married in 1899 and moved to Oklahoma in 1904. They had two children, Gertrude and Theresa. Otto's wife, Winnie, was also a socialist organizer as well as a prominent suffragette. She died in Providence, Rhode Island on November 15, 1960.
- Branstetter listed his occupation as "political work" and his employer as "Socialist Party" on his World War 1 Draft Registration Card dated September 7, 1918, Chicago Draft Board
- Ross, Jack (2015-04-15). The Socialist Party of America. U of Nebraska Press. p. 603. ISBN 9781612347509. Retrieved 14 March 2016.
- U.S., Spanish American War Volunteers Index to Compiled Military Service Records, 1898 Ancestry.com, 2012
- New York Legislative Documents, Volume 12, Page 1497, 1920
- "Jewish Socialists Split: Faction Loyal to National Party Organizes Verband" (PDF), New York Times, 6 September 1921, retrieved 14 March 2016
- "Branstetter, Winnie Estelle Shirley". Encyclopedia of Oklahoma History and Culture. Retrieved 14 March 2016.