Terror Management Theory (TMT) conceptualizes political ideology as a particularly important component of the cultural worldviews upon which people rely for protection from deeply rooted existential fears. This article summarizes the central ideas of this theory and basic supporting evidence and then reviews research on the implications of TMT for understanding ideological conflict, support for leaders, policies, and political violence. It considers the various sources of security upon which people can rely and suggests that chronic and situational activation of specific worldview values is one important determinant of the specific aspects of the worldview that people rely on for security. It also considers research on factors that encourage and discourage violent solutions to political conflicts, the determinants of ideological consistency across diverse issues, and possible explanations for the current political divisiveness that is found in many nations.