A long line of scholarship emphasizes that exposure to migrants, particularly from cultural and ethnic outgroups, makes native-born citizens more tolerant and more open to international cooperation. In this paper, we ask whether this exposure has the same effect on migrants themselves---particularly those who migrate abroad temporarily for employment. While contact may foster tolerance, labor migrants often encounter ethnic outgroups in hierarchical and transactional circumstances; the impact of these encounters on intergroup relations are not well understood. Partnering with local governmental and non-governmental organizations in Mizoram, India, we conducted a randomized controlled trial on cross-border migration in which we connected individuals seeking overseas employment with job opportunities in the Persian Gulf region’s hospitality sector. Two years after the program began, individuals in the treatment group grew significantly more tolerant toward ethnic, cultural, and national outgroups---both toward groups that migrants worked and lived alongside (other South Asians) and toward groups migrants interacted with only in service settings (Middle Easterners and Europeans). These results imply that migrant-native interactions shape attitudes in both directions, and that the contact itself matters more than its nature. This increased tolerance also bolstered support for cooperative foreign policy, such as international trade and diplomatic cooperation; by contrast, it had little effect on attitudes toward national integration. Our study provides the first set of field experimental evidence on how labor mobility in the global economy reshapes the social and political consciousness of migrants, illustrating how globalization holds the potential of altering intergroup relations in the developing world.