This article addresses the role of age-based faultlines in relation to the perceived productive energy of work teams and transformational leadership as a potential moderator of this relationship. Based on social identity and social categorization theory, teams that have strong age-based faultlines— defined as age subgroup formation that is reinforced by internal alignment with other demographic characteristics (tenure and sex)—should show a lower level of perceived productive energy than do teams that have weak faultlines. In teams with high levels of perceived transformational leadership, this effect should be reversed. Study hypotheses were tested on a sample of 664 individuals in 72 teams from a multinational company. Results showed a marginally significant negative relationship between age-based faultlines and teams’ productive energy, although the moderation effect of transformational leadership was found to be significant. These results point toward transformational leadership as a promising strategy for overcoming the negative effects of age-based faultlines in team settings.