Sergio Marchionne (Italian: [ˈsɛrdʒo marˈkjɔnne]; 17 June 1952 – 25 July 2018) was an Italian-Canadian businessman, widely known for his turnarounds of the automakers Fiat and Chrysler, his business acumen and his outspoken and often frank approach, especially when dealing with unpalatable issues related to his companies and the automotive industry.

Marchionne was the chairman of CNH Industrial, the chief executive officer (CEO) of Fiat Chrysler Automobiles (FCA), the chairman and CEO of FCA US LLC, the chairman and CEO of Ferrari, and the chairman of Maserati. He was the chairman of Swiss-based SGS and vice chairman of UBS from 2008 to 2010, as well as the chairman of the European Automobile Manufacturers Association for 2012 (first elected in January 2006). He was a member of the Peterson Institute for International Economics, and the chairman of the Italian branch of the Council for the United States and Italy.

Noted for his keen observations of the automotive industry, Marchionne's insights ranged from frank criticism of his company's own products to a highly regarded 2015 presentation titled Confessions of a Capital Junkie, extolling the benefits of industry consolidation.

Marchionne was widely recognized for turning around Fiat Group to become one of the fastest-growing companies in the auto industry, in less than two years. In 2009, he was instrumental in Fiat Group forming a strategic alliance with the ailing US automaker Chrysler, with the support of the U.S. and Canadian governments and trade unions. Less than two years later, following its emergence from Chapter 11, Chrysler returned to profitability, repaying some of its government loans. In 2014, Fiat and Chrysler merged into a new holding company, Fiat Chrysler Automobiles, then the seventh-largest automobile manufacturer in the world.

Following complications from surgery, Marchionne resigned from all of his positions in July 2018, and he died a few days later. The American business channel CNBC described Marchionne as a "legend" of the automotive industry, while the British newspaper Financial Times considered him as having been "one of the boldest business leaders of his generation".

Marchionne was born in Chieti, Abruzzo, Italy, the son of Concezio Marchionne, from Cugnoli (Abruzzo), and Maria Zuccon from Carnizza (today Krnica, Croatia) near Pula in Istria. His father served as a Carabiniere in Istria, where he met his future wife. Marchionne's grandfather, Giacomo Zuccon, was killed in September 1943 by Yugoslav Partisans near Barban in Istria, while his uncle Giuseppe Zuccon was killed by German troops the same year. In 1945, when the region was occupied by the Yugoslav army, Marchionne's parents moved to Chieti in Abruzzo, where Sergio was born.

At 13, Marchionne emigrated with his family to Toronto, Ontario, Canada, where they had relatives. Carrying dual Canadian and Italian citizenship, he spoke fluent English, French and Italian. Marchionne was a Canadian certified general accountant (FCGA), barrister, and a fellow of the Certified General Accountants of Ontario.

Marchionne attended St. Michael's College School, before completing his undergraduate studies in philosophy at the University of Toronto and earning a bachelor of commerce degree (1979) and an MBA (1985) from the University of Windsor as well as a law degree from Osgoode Hall Law School of York University (1983). He received an honorary doctorate from Walsh College (2013).