This special issue of the Journal of Social Issues focuses on different ways that social history and psychology—always co-constructing each other—matter.  Focused on major events and social movements of the twentieth century, we highlight work that psychologists have done that allow us, as a field, to take seriously the relationships between social-level events and individuals’ identities and self-representations, emotional lives and well-being, approaches to social justice and collective action, motivations and accomplishments. The individual and collective pursuit of social justice makes links between history and psychology visible along with their implications for relations within and between social groups.