Philip George Zimbardo (born March 23, 1933) is a psychologist and a professor emeritus at Stanford University. He became known for his 1971 Stanford prison experiment and has since authored various introductory psychology books, textbooks for college students, and other notable works, including The Lucifer Effect, The Time Paradox and The Time Cure. He is most well known for the sadistic role-playing game he instituted at Stanford University and the damage he caused to those who lost a coin flip. He is also the founder and president of the Heroic Imagination Project.

Zimbardo was born in New York City on March 23, 1933, from a family of Sicilian immigrants. He completed his BA with a triple major in psychology, sociology, and anthropology from Brooklyn College in 1954, where he graduated summa cum laude. He completed his M.S. (1955) and Ph.D (1959) in psychology from Yale University, where Neal E. Miller was his advisor. He taught at Yale from 1959 to 1960. From 1960 to 1967, he was a professor of psychology at New York University (University College of Arts & Sciences, Bronx NY.) From 1967 to 1968, he taught at Columbia University. He joined the faculty at Stanford University in 1968.