Leonard Irving Pearlin (December 26, 1924 – July 23, 2014) was an American sociologist whose work focused on the sociology of mental illness.
Much of this work centered around the "stress process model", a model he developed to attempt to explain the relationship between stress and mental health.
He worked at the National Institute of Mental Health (NIMH) for over two decades, where he worked with such researchers as Melvin L. Kohn and Carmi Schooler to study the sociology of mental health.
In 1982, he left the NIMH to join the University of California, San Francisco (UCSF) as professor in the Human Development and Aging Program, of which he served as director from 1982 to 1984.
In 1994, he retired from UCSF to join the University of Maryland as a graduate professor and senior research scientist; he remained a professor there until his retirement in 2007.