Stacy London (born May 25, 1969) is an American fashion consultant and media personality known primarily for her role as co-host on What Not to Wear, a reality program that features makeovers. After graduating from Vassar College, London started her career as a fashion editor at Vogue and transitioned into being a stylist for both celebrities and designers. While still co-hosting What Not to Wear with Clinton Kelly, she has since moved into fashion reporting for the Today Show and business consulting for several corporations. She is a brand ambassador for Pantene hair products, Woolite detergent, Dr. Scholl's, and Riders by Lee jeans.

London was born and raised in New York City, of Sicilian descent on her mother's side and Jewish descent on her father's. Her stepmother, Victoria, is a romance novelist. Her mother, Joy, worked as a venture capitalist, and her father, Herbert London, is the president emeritus of the Hudson Institute. "We don't see eye to eye on that much politically," she acknowledges, but "he did instill a certain sense of propriety and right and wrong in me, which plays into my fashion sensibility." She also acknowledged him as "the best father in the world." She received her B.A. from Vassar College with a double major in 20th-century philosophy and German literature, and was a member of Phi Beta Kappa. It was during a summer internship in Paris in Christian Dior's PR department that she took a serious interest in pursuing a career in the fashion industry.

London ⁱ/ˈlʌndən/ is the capital city of England and the United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its founding by the Romans, who named it Londinium. London's ancient core, the City of London, largely retains its square-mile mediaeval boundaries. Since at least the 19th century, the name London has also referred to the metropolis developed around this core. The bulk of this conurbation forms the London region and the Greater London administrative area, governed by the elected Mayor of London and the London Assembly.

London is a leading global city, with strengths in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism and transport all contributing to its prominence. It is the world's leading financial centre alongside New York City and has the fifth-largest city GDP in the world (and the largest in Europe). London has been described as a world cultural capital. It was the world's most visited city during 2011 and London Heathrow is the world's busiest airport by number of international passengers. London's 43 universities form the largest concentration of higher education in Europe. In 2012 London will become the first city to host the modern Summer Olympic Games three times.