This chapter begins with an overview of the social scientific, philosophical, and political dimensions of historical materialism (HM). This overview is followed by an elaboration of what HM involves, including its diversity, value, and potential but avoidable pitfalls. Key HM concepts are set out and used to show how capitalism generally and in its recent neoliberal form aims to generate insecurity for labour and security for capital. Rather than being a narrow approach to security that focuses on economics, at its best, HM is a holistic approach that provides a way of putting into perspective and relating the many components of security. It goes on to explore the relationships between HM and approaches to security in wider contexts (realism, liberalism, social constructivism, and gender) and then to various perspectives on security (securitization and the sectoral approach, peace studies, Critical Security Studies, and human security). Accompanying the text are Think Point 4.1 on using HM to understand arms production and the arms trade, and Think Point 4.2 on using HM to understand the connections between development and security. The conclusion provides an overall assessment of the contribution of HM to the scholarship and politics of security and insecurity.