Members of teams are often prone to interpersonal communication patterns that can undermine the team’s capacity to engage in self-learning processes that are critical to team adaptation and performance improvement. We argue that team leader coaching behaviors are critical to ensuring that team discussions that may foster learning new teamwork skills and strategies are unfettered by the tendency of two or more members to exhibit contentious interpersonal communications. We accordingly test a model in which team contentious communication moderates the mediated relationship of team leader coaching behaviors on team innovation effectiveness and team task performance. In a study of 82 work teams, team leader coaching behaviors exhibited indirect, positive relationships with both team innovation effectiveness and team task performance through team learning, but only among teams with an average or higher level of contentious interpersonal communication. We discuss theoretical and practical implications for the leadership of teams.