The adage that there is ‘no security without development and no development without security’ (commonly referred to as the security–development nexus) has become the dominant discourse of Western donor engagement with the developing world since the 2001 terrorist attacks in the United States (US). This thesis argues that the existing literature on the nexus, as seen from a critical neocolonial and securitisation lens, is Western-centric in its parochial attention to the conceptual, policy and programming concerns of the Western donors. As a result, the literature excludes the voices of the local recipient countries on this subject, robbing them of their agency and subjecthood. By doing this, the literature is inadequate in explaining the deeper level politics of the nexus that are present on the ground in the recipient countries. Therefore, this thesis takes a decolonial approach, using a case study of the Kerry-Lugar-Berman Act in Pakistan to explore the politics of the security–development nexus with regard to the issues of ‘sovereignty’ and ‘agency’. The thesis argues that the security–development nexus activates a dialectical power struggle between donor and recipient countries and between different actors within the recipient countries that use the indivisibility of security and development to advance their strategic interests over each other. For instance, the nexus has enabled the US to influence the national security policies and civil–military relationships of Pakistan, challenging its sovereignty. However, the local actors in Pakistan, notably the political and military stakeholders have not been passive bystanders; they, too, have exerted their agency to co-produce the nexus and use it to their own advantage, such as by modernising their armed forces or promoting civilian supremacy in the country. The thesis demonstrates that the security–development nexus is not only a Western donor construct but also actively constructed by recipient countries like Pakistan, which mould it to serve their own interests. Recognising this co-constitutivity allows the prevailing understanding of the security–development nexus to be simultaneously enriched and challenged.