Using the Indonesian annexation of East Timor in 1975 and Vietnam's occupation of Cambodia between 1978 and 1989 as case studies, this article examines how ASEAN understood the principles of non-intervention and non-interference as juxtaposed against the right to self-determination in the 1970s. As ASEAN's first "crises" in its formative years, they illustrate how the bloc's initial norm-making processes evolved as individual member states attempted to make their case for or against intervention. The article contends that ASEAN's principles of non-intervention and non-interference are non-static and adaptive. It also suggests that while ASEAN's normative framework may have been sufficiently accommodative of its members' different standards and approaches towards protecting sovereignty, the right to self-determination and independence in the past, it is questionable whether the adherence to non-interference would be sufficient for the grouping to address the present crisis in Myanmar and future challenges.