Operating as the center of student life, college unions have a central role to teach citizenship, social responsibility, and leadership. Unions can serve as locations for education and conversations about sustainability, as well as for organizations operationally and programmatically engaged in sustainable practices. In this chapter, the authors examine the historical framework of college unions, how a college union functions as a building and a business, and provide some detail on how a college union--with its heart and soul--can be a leader in shaping current and future practices that support the values of sustainability and stewardship. The perspective of stewardship is adopted in this chapter to advance a discussion about college unions as a model for campus sustainability.