The authors investigated the antecedents of team task cohesiveness in service learning classroom environments. Focusing on task commitment and task attraction as key dependent variables representing cohesiveness, and task interdependence as the primary independent variable, the authors position three important task action phase processes as mediators in the analyses. Overall, results provide strong support for hypothesized relationships. Task interdependence in student teams significantly influences task cohesiveness through these action phase processes. The authors highlight important implications for faculty who are interested in how to best structure student teams, particularly when course projects incorporate service learning.