Teacher teams are increasingly common in urban schools. In this study, we analyze teachers' responses to teams in six high-poverty schools. Teachers used two criteria to assess teams' goodness of fit in meeting the demands of their work: whether their teams helped them teach better and whether the team contributed to a better school. Their responses differed notably by school, depending largely on the principal's approach to implementation. In the three schools where teachers assessed teams favorably, principals set a meaningful purpose for teachers' collaborative work, provided structural support and professional expertise for their deliberations, and established safe environments for teachers' on-the-job growth.