Martha Helen Stewart (née Kostyra; born August 3, 1941) is an American business magnate, television host, author and magazine publisher. As founder of Martha Stewart Living Omnimedia, she has gained success through a variety of business ventures, encompassing publishing, broadcasting, and merchandising. Stewart's syndicated talk show, Martha, is broadcast throughout the world, she has written numerous bestselling books, and she is the publisher of Martha Stewart Living magazine.

In 2001, Stewart was named the third most powerful woman in America by Ladies Home Journal. In 2004, she was convicted of lying to investigators about a stock sale and served five months in prison. Stewart began a comeback campaign in 2005, with her company returning to profitability in 2006.

Martha Stewart was born in Jersey City, New Jersey to middle-class Polish-American parents Edward "Eddie" Kostyra (c. 1912 – 1979) and Martha Ruszkowski Kostyra (b. Buffalo, New York, September 16, 1914 – d. Norwalk, Connecticut, November 16, 2007). She lived in Jersey City until the age of 3, when her family moved to Nutley, New Jersey . She was raised in Nutley along with her five siblings . Stewart graduated from Nutley High School in her hometown .