Caste discrimination is a global phenomenon that is not exclusively practiced within any particular religion or belief system. It is traditionally rooted in the Hindu caste system in South Asia, according to which Dalits are considered "outcasts". However, caste systems and the ensuing discrimination have spread into Christian, Buddhist, Muslim, and Sikh communities. Caste discrimination involves massive violations of civil, political, economic, social, and cultural rights, and caste-affected communities are denied a life in dignity and equality. A central feature of caste discrimination is the so-called "untouchability practices," which stem from the notion that different caste groups have varying degrees of purity and pollution, with Dalits and other caste-affected groups being so impure that they can pollute other groups.

In India, the caste system has its origins in ancient India and was transformed by various ruling elites in the history of India, especially during the Mughal period. There are 3,000 castes and 25,000 sub-castes in India, each related to a specific occupation. Negative discrimination on the basis of caste was banned by law in 1948 and further enshrined in the Indian constitution in 1950; however, the system continues to be practiced in parts of India. The Indian government officially recognizes historically discriminated communities of India such as the untouchables under the designation of Scheduled Castes, and certain economically backward castes as Other Backward Class.

Caste discrimination in the United States is a form of discrimination based on the social hierarchy, which is determined by a persons birth. Though the use of the term caste is more prevalent in South Asia, it is also used to describe social stratification in the United States. In 2021, the student body of California State University system passed a resolution against caste discrimination.

In summary, caste discrimination is a form of discrimination based on social hierarchy, which is determined by a persons birth. It is traditionally rooted in the Hindu caste system in South Asia, but it has spread to other communities and countries. Caste discrimination involves massive violations of civil, political, economic, social, and cultural rights, and it is a global phenomenon.