The separate legal personality of ASEAN, an international organization, is a matter of some significance. ASEAN is capable of separate action and can carry rights and obligations on the international plane, as a distinct entity from its Member States. In this Journal, Chen Zhida advances the proposition that ASEAN is entitled to conclude treaties on behalf of its Member States, a practice which, it is argued, should be valid at international law. This paper responds by drawing attention to the difficulties with this argument on technical and conceptual grounds. For technical reasons, it is important to make a meaningful distinction in the ASEAN practice of concluding instruments such as Memoranda of Understandings, which can be distinguished from treaties. At a conceptual level, the treaty practice of ASEAN as a separate legal person must be based on what was consented to by Member States in the ASEAN Charter, a constituent instrument.