Sustainable development is so important that humanity must do its utmost to achieve these goals for the well-being of the present and future generations. WTO members have started to reform WTO rules since the WTO’s Buenos Aires Ministerial Conference in 2017. My thesis describes a possible bright future for readers: WTO members can integrate the UN SDGs into WTO law (i.e., create sustainable trade rules) by establishing a sustainable development club and constitutionalising the WTO. This thesis is structured as follows. Part I, consisting of chapters 1 and 2, explains why WTO law impedes the implementation of trade-related SDGs. Part II consists of chapters 3 and 4, in which I propose the legal approach to review the legitimacy of WTO members’ domestic sustainability measures. I argue that Panels should use the sustainability test. Part III consists of chapters 5, 6, 7, 8, and 9. These chapters describe how WTO members include the legal bases of the sustainability test in WTO rules.