Background Discrimination in health care is an international challenge and a serious obstacle to justice and equality in health. Research objective The purpose of this study was to design a grounded theory of discrimination in health care based on the experiences and perceptions of Iranian healthcare providers and patients. Research design This qualitative study was conducted using by the grounded theory method. Participants and research context Data were collected through semi-structured interviews with 18 healthcare providers including 11 nurses, two physicians, (...) two nurse’s assistants, and three patients in two general hospitals in Tehran, Iran. Participants were selected through purposeful sampling and analyzed simultaneously using the Corbin and Strauss (2015) approach. Ethical considerations The study was approved by the Research Ethics Committee of the University of Social Welfare and Rehabilitation Sciences (Ethics code: IR.USWR.REC.1398.023). Also, after explaining the objectives of the study, all the participants completed and signed the written consent form. Findings The “culture of discrimination” was the study’s core category, reflecting the nature of discrimination in health care. The theory of “culture of discrimination in health care” is the result of five main categories: “individual social stimuli,” “culture of discrimination,” “unintentional discrimination,” “conflict with discrimination,” and “dissatisfaction with discriminatory behavior.” These categories cover the underlying factors, strategies, and outcomes of the discrimination process in health care. Discussion The results of the study showed that nurses and other health care providers experience unintentional discrimination. Unintentional discrimination refers to discriminatory behaviors and practices of health care providers. Conclusion The theory of culture of discrimination in health care can be used as a practical guide to describe and understand the role of health care providers, especially nurses. Further studies with a quantitative approach to applying this theory in medical settings are recommended. (shrink)