This research examines criminal participation of women within domestic terrorism while testing two beliefs. Those beliefs focus on the ruthlessness and lethality of female terrorists as described by Laqueur and the belief that women are more likely to be found within a particular group type (left wing). These two beliefs form the basis of U.S. domestic terrorism policy and need to be evaluated empirically to understand whether and how current terrorism policy needs to be reconsidered in order to address the realities of women’s involvement in domestic terrorism. To describe female criminal participation and to test these beliefs, this research uses the American Terrorism Study (ATS), which aggregates all terrorism investigations conducted by the Federal Bureau of Investigation (FBI) between 1980 and 2002.