This chapter explores the concept of “activist learning for sustainability” and the role of activism and related pedagogies and the relationship to education for sustainable development (ESD). The chapter will reflect on a case study of student-led activism: the initiation of a “sustainable student house” devised and developed by students to allow them to “live what they are learning” and educate other students about sustainable lifestyles. Through reflections from this case this chapter explores: the relationship between the formal, informal, and hidden curricula in inspiring and supporting student activist learning for sustainability; some of the challenges of student-led activist projects, such as the sometimes-difficult relationships between students and university staff, and tensions between the students’ private and public spheres of life at university; and student learning as activists for sustainability. The chapter concludes with recommendations for ESD practitioners engaged in the development of activist learning opportunities. © 2022 John Wiley and Sons, Inc.