This PhD aims to generate a better understanding of corporate social responsibility (CSR) in global production networks. CSR is an umbrella term that deals with voluntary activities undertaken by companies and that indicate an ethos to act responsibly in society. This research focuses on CSR practices that aim towards improving working conditions in outsourced production factories by implementing so-called social standards, which often derive from core norms of the International Labour Organization and intend to secure decent working conditions. While companies claim that they take responsibility for workers via CSR practices, civil society actors like the Clean Clothes Campaign criticize CSR as public relations exercise as companies still fail to take ‘sufficient’ responsibility. Based on this contradiction this PhD aims to reveal the political contestation surrounding CSR and the struggles over CSR between companies and civil society organizations claiming to represent workers in global production networks. The main questions are: What practices do companies use to take responsibility for workers in outsourced production, how do they legitimize these practices, and how are these approaches contested? The research is based on theoretical concepts of ‘shared responsibility’, ‘political CSR’ and ‘democratic legitimacy’. The ‘global production network’ framework and a framework for analysing private regulation, referring to legislative, judicial, and executive regulation, are applied. Empirically, the research analyses two private standards initiatives that define and institutionalize CSR practices, namely the Fair Wear Foundation (FWF) and the Business Social Compliance Initiative (BSCI). The findings are mainly based on 150 qualitative interviews with representatives from companies, civil society, auditing companies, and governments. Additionally, documents are evaluated. Empirical research was undertaken in Europe (mainly Germany & Switzerland) and Asia (India & Bangladesh). The research findings suggest that the CSR practices defined by BSCI and the FWF are based on rather different interpretations of the causes of worker injustice. The BSCI is based on a belief in a concept of liberal democracy. In this view companies do not need to legitimate their activities, as long as they comply with national laws. Responsibility is based on a liability model that blames producers and national governments for neglecting their responsibility towards workers. Companies joining the BSCI take the responsibility of initiating processes in developing countries that demand governments, producers and civil society actors in these countries to take responsibility. In contrast, the approach of the FWF is based on an understanding of ‘structural injustice’ and ‘shared responsibility’. In this view violations of labour rights are identified to be inherent in the complexities of global production networks themselves. No single actor can be blamed for the injustices, and therefore corporations ‘share’ a responsibility, and must engage in public discourses according to their power and abilities, what is seen as a ‘political’ form of CSR.