Although healthcare inequalities by race-ethnicity and nativity have been widely explored, more research is needed to investigate how these inequalities result from structures of racial stratification and immigrant exclusion operating within U.S. health care. My dissertation employs hand coded restricted-access medical record data, linked survey data, and rich administrative data to examine the factors generating healthcare inequalities experienced by both patients and physicians. I contextualize these inequalities within a broader U.S. landscape characterized by structural racism and nativism. In the first chapter, I examine the impact of state immigration policy contexts on healthcare access of U.S. agricultural workers representing various racial-ethnic identities and legal statuses between 2005-2012. I find state-level immigration policy contexts are strongly associated with healthcare access among documented non-White Latinx agricultural workers, who report lower levels of healthcare access and greater barriers to care-seeking in increasingly restrictive policy contexts. In the second chapter, I use hand coded electronic medical record data to examine provider-patient communication disparities. Black and Latinx patients are less likely than White patients to receive provider communication regarding a new incidental medical finding diagnosis. This disparity may reflect interpersonal racism between providers and patients of color, resulting from the perpetuation of racial mythologies in medicine. In the third chapter, I use geocoded data from the American Medical Association to explore whether subgroups of international medical graduates (IMGs) experience career stratification based on their country of medical education. I find IMGs trained in developing countries chart more marginalized U.S. career paths relative to those trained in developed countries, suggesting that nativism and racism within the medical profession intersect to disadvantage physicians from developing countries, who often are also people of color. My dissertation generates empirical evidence to show how racism and nativism operating within the U.S. healthcare system generate inequalities among people of color and immigrants. These findings have important implications not only for our understanding of racial inequality and social stratification broadly, but also for informing policy and intervention to promote equity within U.S. health care.