Ernesto Illy (July 18, 1925 – February 3, 2008) was an Italian food chemist and businessman, known as the chairman of the Illycaffè S.p.A coffee manufacturer.
He was deeply and widely respected, and is considered "an absolute giant" in the world of coffee and espresso, He spearheaded Illy's research into coffee and espresso quality, as summarized in his son Andrea's book, Espresso: The Chemistry of Quality, which was written with Ernesto's assistance.