This chapter considers the role of small states in the complex system of Southeast Asia and Indochina as one of its constituent sub-regions. It discusses the challenge of strengthening regional cooperation through an analysis of the subjective role played by small states as they have responded actively to the regionalism advocated by Association of Southeast Asian Nations (ASEAN) , which, especially since the 1990s, has worked to deepen and expand cooperative relationships with the broader Asian region. The chapter proposes a new scheme for prioritizing the history of Laos's international relationships. Subsequent actions taken by Laos in the Mekong River Basin region can be identified in the transition of its bilateral and multilateral relations with China, Vietnam, Cambodia, Thailand, and ASEAN. Especially among the ASEAN nations, as a federation of small states positioned at the center of a regional formation, the choice of strategies for ensuring security and independence has expanded dramatically and flexibility of conduct has been ascertained.