In this paper we analyse the selected findings of a recent Australia-wide empirical study that investigated the impact of the presence of senior women executives on management cultures. The particular focus of this paper is the university sector. Our analysis of this sector revealed that both men and women clearly believed that the presence of women in senior roles had changed management cultures. We explore participants' descriptions of the nature of that change. Inherent to this discussion are notions of 'critical mass' and 'critical acts'. We define these notions and explore the influences that a critical mass of women in senior roles appears to have had on management cultures in the university sector. We found when women at senior levels reach a critical mass, both women and men believed that women encouraged greater collaboration, more consultative decision making processes and more collegial workplaces. Women were described as showing more 'emotional intelligence'. We consider why descriptions of the changes that women bring to senior management rely so heavily on stereotypical images of male and female behaviours and the implications this has particularly for women managers.