This chapter explores how investment agreements can be drafted and interpreted to ensure that public policy interests to promote sustain able development and to hold foreign investors accountable for human rights are taken into account in investment rule making. It focuses on how tribunals can apply rules of treaty interpretation to consider relevant rules of international law, including human rights law. The chapter considers how states can raise defences that allow the use of other international obligations of a state as a justifiable infringement on the limitation of investor and investment protections. Investment treaty preambles typically reference economic development as the primary objective without referencing the importance of sustainable development and the relevance of human rights protection as suggested in the Southern African Development Community mode Bilateral Investment Treaties. While economic development is important for the protection of human rights, preambles also need to recognise human freedoms, which must thrive for economic development to occur.