Idoia Estornés Zubizarreta (Santiago de Chile, 28 November 1940) is a Chilean-born Spanish historian and writer.

Idoia Estornés Zubizarreta was born in Santiago de Chile in 1940, into a Basque nationalist family exiled due to the Civil War.

Between 1962 and 1966, she completed her studies at the University of Navarra, where she later obtained a doctorate in history in 1988.

Subsequently, she has been the editorial director of the Basque Encyclopaedic Dictionary by Auñamendi and a contributor to various Spanish and French press.

Between 2000 and 2006, she also directed the update of the Illustrated General Encyclopaedia of the Basque Country, devoting herself exclusively to it.