Amy Matilda Williams Cassey was an African American abolitionist and was active with the Philadelphia Female Anti-Slavery Society. Amy Cassey was a member of the group of elite African Americans who founded the Gilbert Lyceum, Philadelphia's first co-ed literary society. The society had more than forty registered members by the end of the first year.

Cassey was born free into a prominent African American family, in New York City, to Sarah and Peter Williams Jr. Her father, Peter Williams Jr., founded and was the pastor of St. Phillips black Episcopal church in lower Manhattan. Cassey was involved in black newspapers and organizations in her early teens. She attended the African Free School for her education in New York City. In 1826 when Cassey was seventeen, she met and married an activist and businessman from Philadelphia named Joseph Cassey. After marrying, she moved with him to Philadelphia.

Cassey was active in the Philadelphia Female Anti-Slavery Society which focused on providing access to opportunities for education, moral reform, and vocational training for the free black community living in Philadelphia. In 1841 Amy and Joseph Cassey along with Robert Douglass, Sr., Jacob White, Sr., John Bowers, Robert Purvis, Sarah Douglass, Hetty Burr, Grace Douglass, Harriet Purvis, and Amelia Bogle founded the Gilbert Lyceum. The Gilbert Lyceum was the first co-ed literary society for African American Philadelphians and included literary and scientific interests.

Joseph Cassey died in 1848, Cassey then married Charles Lenox Remond in 1850. The two moved to Salem, Massachusetts where she continued to be active in civil rights and abolition.[8] In 1853 Cassey brought a successful suit against the management of a Boston theater when she was wrongfully ejected. Cassey died on August 15, 1856 in Salem, Massachusetts.