Ernestine Ygnacio-De Soto (born 1938/1939)[2] is an author, cultural advisor, and former nurse of Barbareño Chumash descent.

[3][2] Ygnacio-De Soto has worked closely with archivist John Johnson for over a decade, in documenting family memories and Barbareño Chumash cultural traditions in to writing.

[2] Ygnacio-De Soto was the illustrator of a children's book which tells one of her mother's cultural stories, The Sugar Bear Story (2005), published by Sunbelt Publications in conjunction with the Anthropology Department of the Santa Barbara Museum of Natural History.

She spoke out in 2019 against a project by the Bacara Resort in Santa Barbara, which aimed to build bathrooms in an area that holds sacred Chumash graves.

[9] The United States National Park Service has devoted a web page to her commentary on Scott O'Dell's book, Island of the Blue Dolphins (1960), in Chapter 7.