Recent events, including the rise of the Islamic State and its overt recruitment of Western women, have once again brought the issue of women participating in terrorist organizations to the forefront. Yet much remains to be understood about why women join terrorist organizations and why groups choose to incorporate them into their structures and operations. Women in Modern Terrorism, which draws from a unique dataset compiled over a decade, tackles these questions and analyzes women’s inclusion in terrorist organizations since the beginning of modern terrorism, covering both religious and ethno-nationalist terrorism and conflict. The text opens with a discussion of the definition of terrorism before examining key issues, such as how and why women join terrorist groups, what women’s inclusion in terrorist organizations reveals about the nature and longevity of both the groups and the conflicts, the future of women’s role in terrorist organizations and attacks (particularly given the rise of new terrorist groups in Syria and Iraq), and the types of attacks women perpetrate and how they compare across groups. By looking at case studies, including Hizballah, Chechnya, the Liberation Tigers of Tamil Eelam, Al Qaeda, Boko Haram, Al Shaabab, and more, this text shows that women’s inclusion in various terrorist organizations is largely a pragmatic choice by the group. It also highlights the cross-pollination of ideas between differently motivated groups. All these issues, along with the role of the media and the Internet in radicalization and recruitment processes, are explored to provide an exhaustive account of the many roles for women in terrorist groups today.