Generational change is radical change that occurs in an organisation or a population as a result of its members being replaced over time by other individuals with different values or other characteristics.
Generational change generally presents both a real and a perceived crisis. In an organisation, the unspoken cultural values held by the longer serving members may be challenged, threatened or abandoned by newer members. In an ecological system, generational change of the representatives of one species may threaten the survival of other species.
Examples include rock n roll in the 1950s over the jazz music of 1920–1945, the counterculture in the 1960s over the conservatism of the 1950s, and hip hop in the 1990s and 2000s over the rock music of the 1970s and 1980s.