This report provides an overview of Social Identity Theory (SIT) and its utility as an integrative framework for the qualitative study of terrorism and violent extremism. SIT is a sociological theory for understanding the effects of social identification on group membership, group behaviour, and intergroup relations. It was designed specifically for the study of intergroup conflict, but scholars have developed a comprehensive analytical apparatus for improving our understanding of multiple aspects both of inter- and intragroup relations and conflict. SIT can serve as scaffolding for organizing our knowledge about terrorism and violent extremism, but also as a foundation for new analytical tools and structures. Following a preface, chapter one demonstrates the need for an integrative analy-tical framework in the qualitative study of terrorism and violent extremism. Chapters two discusses why SIT is suitable as such a framework, and also the main criticisms against it. Chapters four through seven examine the basic hypotheses and implications of SIT and each chapter identifies some to the key implications for the study of terrorism and violent extremism. Chapter eight outlines a particu-larly influential SIT-derived structure for organizing analysis of terrorism - Fathali Moghaddam's "staircase to terrorism" - and chapter nine provides a brief sum-mary and conclusion.