The promotion and protection of investors and their foreign investments have been the focus of the International Investment Law regime since its foundation – it has been its raison d’être. This is reflected in the vast majority of traditional International Investment Agreements, which contain substantive protections for investors whilst only imposing obligations on the States. This asymmetry has been at the centre of the crisis of IIL. On the economic side, multinational enterprises (MNEs) are significant drivers of FDIs, conducting most of them, which can foster economic growth in both the State where they are established or registered (home State) and the States where they invest (host States). Given the economic impact of FDIs and the political risks that foreign investors often face, the framework of IIL to safeguard foreign investments was established. However, there is also a social dimension to regulating MNEs, which is far from being as complete. In the past years, there has been an increasing recognition of their role in guaranteeing the social welfare of the host State’s population. MNEs have a responsibility towards society regarding labor standards, human rights, and the environment. This responsibility, coupled with the increase in asymmetry/imbalance between investors’ rights and States’ obligations, has led to a widespread crisis within IIL, a crisis that has not yet been resolved with increasing calls for more accountability on the investors, leading to a corporate social responsibility (CSR) movement. This Paper seeks to determine whether a balance between investors’ rights and States’ obligations can be achieved through the use of CSR clauses. It questions whether the concept of CSR can/has evolved from soft law to hard law through the increasing incorporation of CSR clauses and other indirect means in IIAs.