Mary Mildred Williams (born Botts, c. 1847 – 1921) was born into slavery in Virginia and became widely known as an example of a "white slave" in the years before the Civil War.
In 1855, her escaped father bought his family's freedom with financial aid from abolitionists, and she, her mother and siblings joined him in Boston, Massachusetts. After arriving in Boston at the age of seven, Williams's photograph became widely distributed, as her appearance was startling for white people who were not used to resembling slaves. She toured with abolitionist Senator Charles Sumner. He used her as an example to confront Northerners with the injustice of slavery, and to raise awareness and funds for the abolitionist cause. Williams was compared to Ida May, the main character in a popular novel of that name; she was a white girl who was kidnapped and sold into slavery.