Despite progress in recent years, Japanese classrooms continue to present challenges for educators seeking to promote language learner autonomy. Adopting an action research/case study design, the present study explored how, in a 5-week student-led project, an intact group of learners could contribute to the development of their own autonomy. Data consisting of questionnaires, observation notes, video recordings, written reflections, and recorded group discussions were analyzed using inductive qualitative coding and descriptive statistics. The students chose to work together as a class, and negotiated and executed a plan of action. The narrative that emerged highlighted the importance of group dynamics in collaborative autonomy development. Student reactions to the project were largely positive, with indications that the project promoted metacognition and learner motivation. This study provides an example of one approach to involving Japanese learners in classroom management to promote a collaborative, interdependent movement towards autonomy.