Madeline DeFrees (November 18, 1919 – November 11, 2015) was an American poet born in Ontario, Oregon, who lived in Seattle, Washington. She joined the Sisters of the Holy Names of Jesus and Mary in 1936 and was known by the name, Sister Mary Gilbert until she was dispensed of her religious vows in 1973. She received her B.A. in English from Marylhurst College, (see Marylhurst University) and an M.A. in Journalism from the University of Oregon.
She has taught at the Holy Names College, the University of Montana and the University of Massachusetts Amherst. While still a nun, she taught at the University of Montana, in Missoula, from 1967 to 1979. Since her retirement in 1985, DeFrees has held residencies at Bucknell University, Eastern Washington University, and Wichita State University. She recently retired from the faculty of the Pacific University low-residency MFA program in Forest Grove, Oregon. She has continued to teach, lecturing at the low-residency MFA program of the Northwest Institute of Literary Arts (Whidbey Writers Workshop) in January 2009.
DeFrees was the author of two chapbooks, two nonfiction books, and eight poetry collections, including Blue Dusk (Copper Canyon Press, 2001), which won the 2002 Lenore Marshall Poetry Prize and a Washington Book Award. She received a Guggenheim Fellowship in Poetry and a grant from the National Endowment for the Arts. Her final collection was Spectral Waves, Copper Canyon Press, 2006. Spectral Waves won the 2007 Washington State Book Award for Poetry. DeFrees died on November 11, 2015, one week before her 96th birthday.
- From the Darkroom, 1964
- When the Sky Lets Go, 1978
- Imaginary Ancestors (chapbook), 1978
- Magpie on the Gallows, 1982 (Copper Canyon Press)
- The Light Station on Tillamook Rock, 1990
- Imaginary Ancestors, 1990
- Possible Sibyls, 1991
- Double Dutch (chapbook), 1999
- Blue Dusk: New and Selected Poems, 1951-2001, 2001 (Copper Canyon Press)
- Spectral Waves, 2006 (Copper Canyon Press)
- Springs of Silence, 1953
- Later Thoughts from the Springs of Silence, 1962
-  Guide to the Madeline DeFrees Papers at the University of Montana
- "The Seattle Review of Books - Madeline DeFrees, 1919 - 2015". seattlereviewofbooks.com.