The convergence of relations between India and the countries of Southeast Asia is a time-tested and enduring phenomenon. Since the days of yore, India is linked with its ‘extended’ neighbours in Southeast Asia through historical, cultural, commercial, defence and strategic bonds. Among the countries of Southeast Asia, Vietnam holds a niche in the domain of bilateral relations with India, and their ties have transcended significant milestones, within the framework of the Government of India’s ‘Look East’, ‘Act East’ and the Indo-Pacific policies. The National Democratic Alliance (NDA-II) government in India acknowledges collaboration with the countries of ASEAN in general and Vietnam in particular in various domains, in which the defence sector deserves emphasis. An important edifice of this cooperation is the ‘Make in India’ and ‘Aatma Nirbhar Bharat’ schemes, envisaged to elevate India’s image as an attractive investment destination by easing the regulatory environment in terms of foreign investment. The incentives offered by opening new sectors to Foreign Direct Investment (FDI), increasing the sectoral limit and simplifying other conditions of the FDI policy, with the objective of providing ease of doing business, reduction of minimum capitalisation, easy exit from projects and accelerating the pace of foreign investment in the country, are of particular relevance. Furthermore, greater emphasis has been laid on collaboration in defence technology, co-development and co-production, offering investment opportunities in defence products manufacturing, supply chain-sourcing opportunity and defence offsets. As the Indo-Pacific region is emerging as a theatre of strategic competition among the various stake-holders, with the challenges posed by a revanchist China to the rules-based liberal international order, the imperative of bolstering defence collaboration between India and Vietnam cannot be over-emphasised. Given this backdrop, the chapter analyses the following: the rationale of the convergence and collaboration between India and Vietnam in the sphere of defence; the potential and trajectory of Indo-Vietnam cooperation in defence within the framework of different governmental policies and initiatives; and identifying the challenges and opportunities.