Marella Agnelli (Italian pronunciation: [maˈrɛlla aɲˈɲɛlli]; born Donna Marella Caracciolo di Castagneto [ˈdɔnna maˈrɛlla kaˈrattʃolo di kastaɲˈɲeːto]; 4 May 1927 – 23 February 2019) was an Italian noblewoman, art collector, socialite, style icon,[1][2][3] and wife of Fiat S.p.A. chairman Gianni Agnelli.

[10] Her father was Don Filippo Caracciolo, 8th Prince of Castagneto, 3rd Duke of Melito, and hereditary Patrician of Naples (1903–1965), from an old noble Neapolitan family dating back to the Kingdom of Naples; he took part in the Italian resistance movement, was the executive secretary of the National Liberation Committee, an undersecretary of the Italian Ministry of Foreign Affairs in the Second Badoglio government,[11] helped overcome objections for the Italian Communist Party to join the government,[12] became secretary for the Action Party, and was general-secretary of the Council of Europe.

[38] In 1973, she created a textile line for Abraham-Zumsteg, for which she was awarded the Resources Council's Roscoe (the design trade's equivalent of the Oscar) in 1977.

[48] Into the 21st century, she oversaw the opening of the Renzo Piano-designed art gallery Pinacoteca Giovanni e Marella Agnelli, built on the roof of the former Lingotto Fiat factory in Turin.

[55][56] The reserved, patrician tastemaker, and socialite Agnelli was known for her inclusion in Truman Capote's the Swans, a circle of wealthy, stylish, and well-married women friends whose company he adored because, in his words, they "had created themselves, as he had done", and "had stories to tell".

[57] According to Capote, Agnelli was "the European swan numero uno", one of the youngest in a group that included Babe Paley, Gloria Guinness, C. Z.

In her autobiography, Washington Post publisher and Capote friend Katharine Graham recounted that the author once told her that if Paley and Agnelli were "both in Tiffany's window, Marella would be more expensive.