Humans are fundamentally social animals, and a large portion of the human brain is dedicated to social cognition—the set of mental functions and processes that scaffold our ability to observe, understand, and interact with others. While early philosophers and scientists relied on observation or isolated cases of brain damage to gain insight into social cognition, the advent of new technologies, including noninvasive neuroimaging, has opened a new window into the brain regions that support social cognition in humans, referred to as the social brain. These technologies have elucidated with new precision that individual brain regions are specialized for a variety of social functions including comprehending language, processing faces and emotions, anticipating what a social partner might do next, and even thinking about others’ thoughts. While the building blocks for the social brain are present from birth, individual regions continue to develop into adulthood and are shaped by experience.