In data-driven collaboration, the teacher and library media specialist (LMS) have a prolonged and interdependent relationship as they do in all collaboration. Units and projects are team-planned, team-taught, and team-assessed. The partners share goals, have carefully defined roles in the process, and plan comprehensively based on the results of evidence of student knowledge, skills, and learning, such as grade level standardized assessments. This article cites several examples in which data-driven collaboration is used to address deficits in student learning. It then discusses the benefits of data-driven collaboration to teachers, students, and LMS.