<p>This paper investigates the diversity within research teams, with a particular focus on the individual characteristics of team leaders. To achieve this, we test four hypotheses using data on 46,158 leaders from 31,869 research teams in Brazil, which together accounted for 51,275 interactions with external partners. First, we investigate whether shared leadership in scientific teams fosters greater collaboration with external partners compared to teams with a single leader. Second, we evaluate whether the presence of female leaders in scientific teams influences the extent of external collaborations. Third, we analyze whether non-White leaders affect the level of cooperation with external partners. Finally, we explore whether diverse shared leadership, incorporating variation in both race/ethnicity and gender, impacts the number of external partnerships and collaborations. We use data from the Directory of Research Groups (<i>Diretório dos Grupos de Pesquisa—</i>DGP) to test these hypotheses and employ Poisson and Negative Binomial regression techniques. Our findings reveal that shared leadership within scientific teams has a positive influence on the number of collaborations with external partners. However, the presence of female leaders—whether in single or shared leadership configurations (e.g., female–female, male–female, or female–male leadership)—is associated with a significant reduction in external collaborations. Additionally, teams led by non-White researchers—either as sole leaders or in shared leadership structures—are less likely to collaborate externally compared to teams led by White researchers. Finally, leadership groups composed exclusively of ‘Shared White Leadership,’ ‘Shared Male Leadership,’ or ‘Shared Female White Leadership’ do not exhibit statistically significant differences from the reference group, ‘Heterogeneous Shared Leadership,’ in terms of external collaborations.</p>