There is an increase in the role played by non-state security actors in daily lives and in politics during the last three decades. Although a number of different questions and issues related to private security in different contexts are discussed within the existing literature, there is a lack of solid critical political economy analysis of the increasing role played by non-state security actors. This thesis examines the question of how we can understand or make sense of the increasing role played by non-state security actors from a critical political economy perspective. While examining this question, this thesis brings in a neo-Marxist approach by attending to the state-market-security nexus. By considering the privatization of security from a critical political economy perspective, this study focuses on capital accumulation at the global and local level through examining some Western and African countries. Additionally, the thesis makes a historical and contemporary analysis of privatization of security against the background of state’s role in security field. In this way, this thesis emphasizes the need for going beyond the existing literature on privatization of security by considering the politics of security as a tool of order which legitimizes the power of the state in protecting capitalist accumulation and the hegemony of capital.