Naval modernization is an extremely expensive, time-consuming, and a relativelyrare phenomenon. Scholars have proposed various arguments to explain thisprocess ranging from bureaucratic politics, to nationalism, and to the securitydilemma. The Nexus of Naval Modernization in India and China demonstratesthat from 1990 until 2020, the primary driver of naval modernization resultedfrom a strategic rivalry. Key to strategic rivalries is perceived threat perceptionsthat cause decision makers to prepare for worst-case scenarios when tryingto decipher their enemy's behaviour. When a state believes it is threatened bya rival's naval power it is likely to pursue its own form of naval modernization forself-protection. Importantly, rivalries do not exist in a vacuum and are frequentlylinked. This project will reveal how the interconnected nature of rivalries canalso cause naval modernization. Through a close examination of scholarly works,government documents, and in-depth focused interviews with experts based inIndia, China, Australia, and the U.S. Colley argues that while strategic rivalry isnot the only driver of naval modernization, it is the most compelling explanation.Other arguments are frequently embedded within the strategic rivalry modeland thus are best seen as only partial drivers. This study contributes to the rivalryresearch program as well as the policy and security studies literatures.