世代（英语：Generation），是指用来划分时间与群体的名词。

又称人群世代，是指具有相同的出生年代及成长背景（包含行为模式）的特定人群，其成长背景，跟国家当时的社会、教育、政治、经济、价值观有很大的关系。

Generation is the act of producing offspring. In kinship terminology, it is a structural term designating the parent-child relationship. It is also known as biogenesis, reproduction, or procreation in the biological sciences. The term is also often used synonymously with cohort in social science; under this formulation the term means "people within a delineated population who experience the same significant events within a given period of time". Generation in this sense of birth cohort, also known as a "social generation", is widely used in popular culture, and has been the basis for societal analysis. Serious analysis of generations began in the nineteenth century, emerging from an increasing awareness of the possibility of permanent social change and the idea of youthful rebellion against the established social order. Some analysts believe that a generation is one of the fundamental social categories in a society, while others view its importance as being overshadowed by other factors such as class, gender, race, education, and so on.