Robert S. Siegler is an American psychologist and professor of psychology at Columbia University. He is a recipient of the American Psychological Association's 2005 Distinguished Scientific Contribution Award.
He specializes in the cognitive development of problem solving and reasoning in children. Three areas of particular interest to his research are strategy choices, long-term learning, and educational applications of cognitive-developmental theory. He proposed the 'overlapping waves' model of cognitive development in 1996.
Siegler received a B.A. in psychology from the University of Illinois in 1970 and a Ph.D. in psychology from SUNY Stony Brook in 1974, and he has been employed at Carnegie Mellon University until 2018, where he was a colleague of Herbert A. Simon. In 2018, he started a faculty position at the Teachers College, Columbia University as the Jacob H Schiff Foundations Professor of Psychology & Education.