Identity development is conceptualized as a series of distinct stages in the developmental pathway, including acquisition of self-knowledge, establishment of independence and personal continuity, and acquisition of a sense of affiliation. For those negotiating more than one cultural/racial/ethnic identity, a unique set of stages may be undertaken in the development of identity, particularly during the transition from adolescence to adulthood. Although the sociocultural factors that shape identity development are relatively well-conceptualized, much less well understood are the biological mechanisms that facilitate identity development throughout the lifespan for both majority and minority group members. This chapter discusses sociocultural and biological pathways of identity development through the lens of cultural neuroscience, elucidating how dynamic culture-biology interactions shape the development of social identity in majority and minority group members and the etiology underlying adaptive social development in people living in monocultural and diverse multicultural communities.