Diversity, equity, and inclusion (DEI) are organizational frameworks which seek to promote the fair treatment and full participation of all people, particularly groups who have historically been underrepresented or subject to discrimination on the basis of identity or disability. These three notions together represent "three closely linked values" which organizations seek to institutionalize through DEI frameworks. Some experts say diversity and inclusion should be decoupled in some cases. Some frameworks, primarily in Britain, substitute the notion of "equity" with equality: equality, diversity, inclusion (EDI). Other variations include diversity, equity, inclusion and belonging (DEIB), justice, equity, diversity and inclusion, or diversity, equity, inclusion and access.

Diversity within groups is a key concept in sociology and political science that refers to the degree of difference along socially significant identifying features among the members of a purposefully defined group, such as any group differences in racial or ethnic classifications, age, gender, religion, philosophy, politics, physical abilities, socioeconomic background, sexual orientation, gender identity, intelligence, physical health, mental health, genetic attributes, personality, behavior, or attractiveness.