This article studies the role of stability in team members’ relations as a determinant of performance in the Italian ‘Serie A’ Soccer League. The dataset includes all the players in the 35 teams that have competed in the ‘Serie A’ from the 1994–95 up to the 2002–03 season. The results show that team stability and longevity of team relationships have a positive impact on performance. Moreover, there is weak evidence that team stability is beneficial up to a critical point, after which it might be detrimental. The article discusses these and other findings, and also how these results contribute to the literature on teams.