"Does identity—one’s concept of self—influence economic behavior in the labor market? I investigate this question in rural India, focusing on the effect of caste identity on labor supply. In a field experiment, casual laborers belonging to different castes choose whether to take up various real job offers. All offers involve working on a default manufacturing task and an additional task. The additional task changes across offers, is performed in private, and differs in its association with specific castes. Workers’ average take-up rate of offers is 23 percentage points lower if offers involve working on tasks that are associated with castes other than their own. This gap increases to 47 pp if the castes associated with the relevant offers rank lower than workers’ own in the caste hierarchy. Responses to job offers are invariant to whether or not workers’ choices are publicized, suggesting that the role of identity itself—rather than social image—is paramount. Using a supplementary experiment, I show that 43% of workers refuse to spend ten minutes working on tasks associated with other castes, even when offered ten times their daily wage. This paper’s findings indicate that identity may be an important constraint on labor supply, contributing to misallocation of talent in the economy."