PurposeThe use of linear models has major limitations for accurately representing the true link between gender diversity and organizational performance. This study aims to explore two curvilinear models and tests which one – the U-shape or the inverted U-shape – best represents the gender diversity–performance link at two hierarchical levels: the board of directors and the workforce.Design/methodology/approachBoth models are tested using data collected from a representative sample of Spanish educational organizations, which are dominated numerically by women, although women are still slightly underrepresented in managerial positions.FindingsThe results show the existence of an inverted U-shape and, therefore, the existence of a potential “optimal” level of gender diversity for both the board of directors and the workforce. While the highest performance by the board of directors is attained when the proportion of women and men is balanced in the workforce, the highest level of performance is attained when the proportion of women is greater.Originality/valueThere are hardly any studies simultaneously exploring the gender diversity–performance linkage at two hierarchical levels where the proportion of women/men is substantially different: the board of directors and the workforce. Thus, this study contributes to better know whether such relationship is dependent on the hierarchical position. It is important to know this because each level is related to different functions and tasks and shape a social status that can significantly influence performance.