Drawing on the work of psychologists Loevinger (1976) and Kegan (1982) and their concept of Adult Ego Development (AED) and evidence collected of school leadership behaviour in the Netherlands and England, this chapter introduces the notion that the ego state of a school principal is linked to them enabling inclusive practices within their schools. The argument is that social justice leadership is connected with a leader’s disposition towards inclusive leadership. The stages of AED are presented briefly and applied in an exploration of the findings from three examples surveyed in the field: two in the Netherlands and one in England. The implications of these findings inform recommendations for principalship preparation and development.