Eduardo Zamacois (17 February 1873 – 31 December 1971) was a Spanish novelist. His uncle was the painter Eduardo Zamacois y Zabala.
Born in Pinar del Río, Cuba, his family lived briefly in Brussels and Paris before settling in Madrid. Leaving college to pursue journalism, he edited El Cuento Semanal and Los Contemporáneos, and, from 1897, worked for the weekly Germinal. Later he moved to Barcelona to write for El Gato Negro and ¡Ahí Va! before founding Vida Galante.
His first fiction was erotic, but realistic in its depictions of ordinary life. From 1905 it took a socialistic form as he grew to sympathise with the Republican cause. During World War I he lived in France, working as a correspondent for La Tribune. He returned to Spain and continued to write prolifically until the outbreak of the Spanish Civil War. He was a war correspondent in Madrid until 1937, and then in Valencia and Barcelona, where he published El asedio de Madrid ("The Siege of Madrid", 1938). After Barcelona's fall he fled to France, and thence to the US and Mexico, before settling in Argentina, where he eventually wrote his memoirs, Un hombre que se va... (1964). He died in Buenos Aires in 1971.
- Sang Joo Hwang. Vida y obra de Eduardo Zamacois (1873–1971). Universidad Complutense de Madrid Facultad de Filología, 1996.
- Janice J. Soler. "Eduardo Zamacois, a Forgotten Novelist." Kentucky Romance Quarterly, Volume 29, Issue 3 (1982), pages 307-322.