There is increasing media attention pointing to diverging generational perspectives and intergenerational rifts on major social, environmental, and political issues. This is of particular interest in social movement organizations, where members’ involvement and dedication stem from their identification with organizational values and goals, such as environmentalism or peace. Drawing on Mannheimian conceptions of sociological generations formed around transformative political periods, this article explores how different generational perspectives trickle into organizations and, subsequently, how the intergenerational encounter shapes organizations. I explore how social generations form around critical junctures, namely, transformative political periods, and adopt different ideologies, which, in an organizational context, can lead to intergenerational confrontation and organizational change. This article builds on ethnographic research and an in-depth case study of a cross-border environmental cooperation organization operating in the Israel and Palestine context, demonstrating how the height then failure of the Oslo peace process created two political generations of peace and environmental activists, with different approaches to peace and environmental engagement within the same organization, leading to intergenerational negotiation, shaping the organization over time.