Prudence Crandall (September 3, 1803 – January 27, 1890) was an American schoolteacher and activist. She ran the Canterbury Female Boarding School in Canterbury, Connecticut, which became the first known school for African American girls ("young Ladies and little Misses of color") in the United States led by a white woman. She was the sister of Reuben Crandall, the defendant in the Trial of Reuben Crandall.

In 1832, when Crandall admitted Sarah Harris, a 20-year-old African American woman, to her school, she created what can be considered the first known integrated classroom in the United States. Following the decision, parents of white students began to withdraw their daughters. Rather than ask Sarah to leave, she decided that if white girls would not attend with the Black students, she would focus on educating African American girls to become teachers. She was arrested and spent a night in jail. Repeated trials for violating a Connecticut law, passed explicitly to make her work illegal, as well as violence from the townspeople, resulted in Crandall being unable to keep the school open safely. She left Connecticut and never lived there again.

Much later, the Connecticut legislature, with lobbying from Mark Twain, a resident of Hartford, passed a resolution honoring Crandall and providing her with a pension. She died a few years later, in 1890.

She was named the State Heroine of Connecticut by the Connecticut General Assembly in 1995.

Prudence Crandall was born on September 3, 1803, to Pardon and Esther Carpenter Crandall, a Quaker couple who lived in Carpenter's Mills, Rhode Island, in the town of Hopkinton. She had two brothers, Reuben and Hezekiah, and a sister, Almira. When she was about 10, her father moved the family to nearby Canterbury, Connecticut. As her father thought little of the local public school, he paid for her to attend the Black Hill Quaker School in Plainfield, 5 miles (8 km) east of Canterbury. Her teacher, Rowland Greene, was opposed to slavery, and much later gave an address, published in William Lloyd Garrison's The Liberator, on the necessity of education for Black children and adults. In that address, he commended Isaac C. Glasgow for sending two of his daughters, "exemplary young women", to his former student's school.

Crandall attended the New England Yearly Meeting School, a Quaker boarding school in Providence, Rhode Island when she was 22. After graduating, she taught at a school in Plainfield. She became a Baptist in 1830.

In 1831 she and her sister purchased the Elisha Payne house to establish the Canterbury Female Boarding School, at the request of Canterbury's elite residents, to educate young girls in the town. Together with the help of a maid, the two women taught about forty white girls in different subjects including geography, history, grammar, arithmetic, reading, writing, chemistry, astronomy, rhetoric, and French. As principal of the boarding school, Prudence Crandall was praised for her ability to educate young girls. The school flourished and was well received in the community.

Although Prudence Crandall grew up as a North American Quaker, she admitted that she was not acquainted with many Black people or abolitionists. She learned of the hurdles white Americans created for Black adults and children through the abolitionist newspaper The Liberator, which she learned of through her housekeeper, "a young black lady", whose fiancé was the son of the paper's local agent. When discussing the impact of reading The Liberator, she shared that the articles and essays caused her to, "contemplate[d] for a while, the manner in which I might best serve the people of color."