Sydney Biddle Barrows (born January 14, 1952), also known as the Mayflower Madam, was an American prostitute and madam. After her escort service was busted, she gained worldwide notoriety in part because she was part of the high-class Biddle family and had Mayflower heritage.

After a short career in fashion, she was introduced to the world high-class prostitution and founded an escort service called Cachet which existed in New York City from 1979 to 1984. After her arrest she published an autobiography, Mayflower Madam which later became a film of the same name, starring Candice Bergen. She has written two subsequent books on modern sexual etiquette, and as of 2004 lives in New York City.