Janet Auchincloss Rutherfurd (June 13, 1945 – March 13, 1985) was an American socialite and half-sister to Jacqueline Kennedy Onassis and Lee Radziwill.
Born Janet Jennings Auchincloss, she was the only daughter of Hugh D. Auchincloss, Jr., a wealthy stockbroker and lawyer, and his third wife, the former Janet Lee Bouvier. She had a younger brother James Auchincloss (b. 1947). It was his third marriage and her second, and both had children from their previous marriages, including Jacqueline Kennedy Onassis.
Janet Auchincloss made her debut in 1963. She studied at the Potomac School in McLean, Virginia, and Miss Porter's School in Farmington, Connecticut, the alma mater of her half-sisters Jacqueline and Lee. She went on to study music history at Sarah Lawrence College. She briefly dated future Senator and Presidential candidate John Kerry.
On July 30, 1966, she married Lewis Polk Rutherfurd, a recent graduate of Princeton University and future financier. The couple moved to Hong Kong, where she later founded an overseas chapter of the League of Women Voters. They had three children: Lewis, Andrew, and Alexandra.
Janet Rutherfurd died of cancer at the age of 39 in a Boston hospital in March 1985, with her half-sister Jackie by her side.