No inter-governmental organization has experienced a more diverse relationship with civil society than the World Bank, ranging from close collaboration to hostility. This chapter examines the evolving threads of that relationship and how it has impacted on the Bank’s programs, policies, operational norms and institutional culture. Civil society organizations (CSOs) of different forms have had a profound impact on many aspects of the Bank’s business and have exposed and widened the heterogeneity inherent in an institution whose professional staff come from a wide variety of disciplines and whose management ethos encourages innovation.