In this article, the authors report changes in mathematical disposition, participation, and competencies within a group of Pasifika students as a teacher established the discourse of mathematical inquiry and argumentation. Within a classroom-based design approach, the teacher used a communication and participation framework tool to support students to engage in a range of collective mathematical practices. Drawing on analyses of student interviews conducted over one school year, the authors provide a narrative that illustrates how changes in agency and accountability accompanied shifts in the mathematical inquiry discourse. The results show positive learning outcomes for Pasifika students when the general and mathematical obligations attend to the cultural, social, and mathematical well being of all students in mathematics classrooms.