Recent developments in investment arbitration have reaffirmed that corporations are not only recipients of rights under bilateral investment treaties, but also subjects of international law and can thus bear at least some human rights obligations under international law. Moreover, in a growing number of cases such as Philipp Morris, civil society intervened as third party by relying heavily on human rights arguments, thus enabling affected communities to voice their interests. The present contribution thus investigates the multiple roles of human rights in investment law and arbitration. It argues that human rights play an important role for state parties, foreign investors, and affected communities alike. They are not only conflicting and complementary to investment treaties, but can both expand and restrict the scope of jurisdiction of investment tribunals. For states, investors, and third parties alike human rights can be used as a sword or a shield in international investment law and arbitration. The different roles human rights play in investment law and arbitration very much depend on the underlying concept of human rights.