We provide a developmental account of civic engagement—specifically, political participation. Civic engagement is more likely among people with politicized identities, an activist stance, and an interest in diverse peers. The form of civic engagement (focused on transmission of parental values or on social change) is shaped by different generations' relative tendency to identify horizontally (with each other) or vertically (with previous generations). Adolescence is proposed as a formative period for the development of a politicized identity and student activism as providing an opportunity to develop both personal efficacy in the political realm and experience working toward a goal with diverse peers. The intersection of late adolescence with periods of intense social discontinuity increases within-generation identification and decreases interest in cross-generational transmission of values. Young American women in the middle to late 20th century experienced such a confluence of factors, and we focus on studies of women's political participation and development of politicized identities at this time. Thus, forms of civic engagement are shaped not only by individual experiences but also by cohort or generational identity.