Off-task activity is ubiquitous in classrooms, yet little understood. Building on recent work that illustrates the utility of off-task activity to disrupt relations of power among students, this article explores the potential functions of off-task participation during collaborative mathematics problem-solving. We examined 56 instances of off-task participation across 12 collaborative problem-solving sessions in a fourth grade classroom during a collaborative inquiry unit on place value. Results show that the majority of instances functioned to support the collaborative problem-solving process. Further, off-task participation often succeeded in shifting collaborative dynamics after on-task bids to shift dynamics failed. Off-task activity seemed to introduce new storylines that served as discursive tools to navigate local social hierarchies. We close by situating an understanding of the resources that students bring into collaborative learning through off-task activity within conversations on inclusive pedagogies. Educational Impact and Implications Statement This study found that off-task activity can often help students manage collaborative dynamics during mathematics small-group work. Off-task activity helped students warm up to collaboration, gain the attention of others, recruit others into participation, gain access to collaboration, extend the task, and resist concentrated authority. Moment-to-moment analysis of four vignettes from the study show that the storylines introduced by off-task activity offered students new ways of being and relating that helped shift dynamics. These results suggest that off-task activity offers resources for students to manage their participation and may be an important characteristic of inclusive, student-centered, collaborative classrooms.