Currently, White supremacy is the greatest terror threat, domestic or international, for the United States, accounting for 73 percent of domestic terror fatalities between 2009 and 2018. As such, this unique aspect of terrorism demands the attention of not only society but also researchers. The first section of this chapter examines the historical roots of White supremacy and White supremacist violence. The second section examines the underlying ideologies that drive these movements and the violence they engage in. The third section explores many of the White supremacist groups that operate within the United States, organizing them by the group’s motivations such as political influence, religious, or youth culture. The fourth section focuses on the current empirical research on White supremacy, specifically the extent of this violence, entry into these groups, and desistance from White supremacy. The chapter concludes by noting areas for future research on White supremacy and domestic terrorism.