Harriet Winslow Sewall (June 20, 1819 in Portland, Maine – April 19, 1889) was an American poet, and editor of the collected letters of Lydia Maria Child.

Winslow was born in Portland, Maine, June 20, 1819 into a Quaker family, where she was educated at a boarding school in Providence, Rhode Island.

She was, at least in her early years, interested in transcendentalism and animal magnetism; and arguably more practically engaged with contemporary anti-slave and women's rights movements.

He soon became ill, relinquishing his job and placing the burden of support on Harriet, who was assisted by her relatively wealthy family.

[1] In 1857, she married her late sister's husband the lawyer and abolitionist Samuel Edmund Sewall and in 1861 her father died, providing her with a "moderate fortune" enabling her to pursue philanthropic interests.