Marilyn Hacker (born 1942) is an American poet, critic, and reviewer. Her books of poetry include Going Back to the River (1990), Love, Death, and the Changing of the Seasons (1986), and Presentation Piece (1975), which won the National Book Award.
She was born in Bronx, New York and attended the Bronx High School of Science, where she met Samuel R. Delany. The two married and had a daughter, Iva, and later divorced.
Hacker is an important contemporary lesbian writer and activist, and often employs strict poetic forms in her poetry, as with Love, Death, and the Changing of the Seasons, which is a verse novel in sonnets. She is also recognized as a master of "French forms," particularly the villanelle.
Hacker appears in Heavenly Breakfast, Delany's memoir of a New York City commune during the so-called Summer of Love in 1967.