This chapter commences by outlining, first, the empirical basis for the claim that Southeast Asia can be recognized as an identifiable region. The chapter then outlines the circumstances that eventually motivated the political elite, in several of the Southeast Asian states, to pursue a regional order that embraced, at least rhetorically, multilateralism as a building block in the common pursuit of stability and economic advancement. The chapter the follows with an assessment of the imperatives behind the formation of ASEAN together with the nature of the institutional order established by its formative instrument – the Bangkok declaration. The final section of the chapter analyses the performance of ASEAN during it early years. While ASEAN was initially limited in both its form and intent, the chapter reveals that ASEAN’s formation coincided with a significant improvement to the original members’ intramural relations.