The Indo-Pacific region has become the epicenter of geopolitical contestation and collaboration in the 21st century. The United States, recognizing the strategic significance of this maritime expanse, has articulated the Indo-Pacific Strategy to foster a free, open, inclusive, and rules-based order. Japan and India, as major powers in the region, are integral to the success of this strategy. This chapter delves into the trilateral partnership among the U.S., Japan, and India, examining its historical evolution, geopolitical interests, economic engagements, and security collaborations within the context of the Indo-Pacific. The study reveals that the confluence of interests among the U.S., Japan, and India is pivotal in shaping the Indo-Pacific narrative and in countering challenges to the rules-based order, particularly from a rising China. The chapter concludes with policy recommendations for strengthening the trilateral partnership and for ensuring a stable and prosperous Indo-Pacific region.