AbstractImmigration has been shown to drive ethnocentrism and anti‐globalization attitudes in native‐born populations. Yet understanding how global integration shapes intercultural relations also necessitates clear evidence on how migration affects the attitudes of migrants. We argue that migration can foster tolerance, cosmopolitan identities, and support for international cooperation among migrants who experience sustained contact with other cultural groups. We evaluate this theory with the first randomized controlled trial resulting in overseas migration, which connected individuals in India with job opportunities in the Persian Gulf region's hospitality sector. Two years after the program began, individuals in the treatment group were significantly more accepting of ethnic, cultural, and national out‐groups. Migration also bolstered support for international cooperation and cultivated cosmopolitan identities. Qualitative and quantitative evidence links these changes to intercultural contact overseas. By focusing on migrants rather than native‐born individuals, our study illustrates how cross‐border mobility can facilitate rather than undermine global integration.