This article examines the China-led Lancang-Mekong Cooperation (LMC) as an institutional balancing strategy against the external pressures from other existing mechanisms, such as the US-Mekong Partnership (UMP), the Mekong-River Commission (MRC), and the Mekong-Japan Cooperation (MJC). In contrast to another China-led multilateral initiative (i.e. the Asian Infrastructure Investment Bank), the LMC has received significantly less attention by the media, scholars, and state actors, as the LMC is limited to five states in Southeast Asia that are often not viewed as major players in world politics. Because our main focus is examining the institutional competition that exists in the Mekong, we explain this competition in the region, with China’s LMC being our main focus. By drawing on the concept of institutional balancing, we explain both why China is doing this and the pattern of great powers that are engaged in institutional competition in the Mekong. The article’s findings indicate that China has yet to achieve its balancing objective, as most LMC members are not willing to exclusively side with China.