Richard E. Mayer is an American educational psychologist who has made significant contributions to theories of cognition and learning, especially as they relate to problem-solving and the design of educational multimedia.

Mayer's best-known contribution to the field of educational psychology is a multimedia learning theory, which posits that optimal learning occurs when visual and verbal materials are presented together simultaneously. He is the year 2000 recipient of the E. L. Thorndike Award for career achievement in educational psychology, and the winner of the 2008 Distinguished Contribution of Applications of Psychology to Education and Training Award from the American Psychological Association.

He was ranked #1 as the most productive educational psychologist in the world from 1997–2001. He is the author of more than 390 publications including 23 books on education and multimedia. He received a Ph.D. in psychology from the University of Michigan (1973) and served as a Visiting Assistant Professor of Psychology at Indiana University from 1973–1975. Mayer is a Professor of Psychology at the University of California, Santa Barbara (UCSB) where he has served since 1975.