With the proliferation of investor-state treaty arbitration, international investment law has been increasingly caught in a “legitimacy” crisis, with concerns looming large over resultant disruptive effects on human rights. Amid existing scholarship seeking to recalibrate the balance between investment protection and public interests, what is relatively undertheorized is a public international law dimension. In this regard, this Article explores the role of human rights law in integrating human rights considerations into investment tribunals’ decision-making, bridging the normative divide between international investment law and human rights. It makes three contributions. First, it systemizes the normative tensions and potential conflicts between international investment law and human rights, analyzing the primary manifestations and root causes thereof. Second, from the position of a respondent state, this Article typologizes the application of human rights law to investor-state treaty disputes, providing legal grounds to alleviate the potential conflicts between investment protection and human rights. In so doing, it also provides a clearer clarification of the relationship between international investment law and human rights law. Third, this Article evaluates the relative strengths and weaknesses of these human rights arguments, shedding light on how international investment agreements could be reformed to better balance investment protection with noneconomic issues.