Purnell Whittington Choppin (July 4, 1929 – July 3, 2021) was an American virologist. He served on the faculty of Rockefeller University for nearly thirty years, becoming the Leon Hess Professor of Virology. He moved to the Howard Hughes Medical Institute in 1985, became the president of the institute in 1987, and retired in 1999, succeeded by Thomas Cech. Until his death in 2021, he was the chair of the Scientific Advisory Board at the Center for the Study of Hepatitis C, supported by a university consortium consisting of Rockefeller, Weill Cornell Medical College, and New York-Presbyterian Hospital.