Blood purity

Blood purity and related terms may refer to:
 * Racial hygiene, an approach to eugenics in the early 20th century especially by Nazi Germany
 * Blood quantum laws, tribal laws in the United States defining Native American status
 * Limpieza de sangre, blood purity laws in Medieval Spain stipulating a social hierarchy based on ancestry
 * Blood purity, a fictional concept of wizarding ancestry in the Harry Potter series
 * Pureblood, a term used in COVID-19 anti-vaccine activism to denote people who have not been vaccinated