Robert Sapolsky is an American academic, neuroscientist, and primatologist. He is the John A. and Cynthia Fry Gunn Professor at Stanford University and is a professor of biology, neurology, and neurosurgery. Sapolsky's research has focused on neuroendocrinology, particularly relating to stress. He is also a research associate with the National Museums of Kenya.

As a neuroendocrinologist, Sapolsky has focused his research on issues of stress and neuronal degeneration, as well as on the possibilities of gene-therapy strategies for protecting susceptible neurons from disease. He is working on gene-transfer techniques to strengthen neurons against the disabling effects of glucocorticoids. Sapolsky spends time in Kenya every year studying a population of wild baboons in order to identify the sources of stress in their environment, and the relationship between personality and patterns of stress-related disease in these animals.

Sapolsky has vigorously argued for a deterministic view of human behavior. According to him, "there is no free will, or at least that there is much less free will than generally assumed when it really matters". Sapolsky argues that human actions are determined by neurobiology, hormones, childhood, and life-circumstances.