Ina Sizer Cassidy (1869-1965) was a writer and active member of the Santa Fe arts community who spent most of her life in New Mexico serving as the Director of the Federal Writer's Project, a participant of the New Mexico Association on Indian Affairs as well as the Spanish Colonial Arts Society and Daughters of the American Revolution.

Ina Sizer Cassidy was born on a ranch in Colorado and later moved to Santa Fe in January 1912. During her life, she and her husband Gerald were an active participant of the Santa Fe arts community. During her life, she was the director of the Federal Writers Project in New Mexico, a writer on the subjects of artists and art, a Director of the Federal Writer's Project in New Mexico, and an author who wrote articles about art and artists for the New Mexico Magazine. On top of this, she participated in the New Mexico Association on Indian Affairs, the Spanish Colonial Arts Society, the Historical Society of New Mexico, was a founder of the Folklore Society of New Mexico, and was active in the Daughters of the American Revolution. Having lived for almost 96 years, she died in 1965.