This dissertation investigates the relationship between cultural diversity in top management team (TMT) and organisational outcomes. The theoretical framework developed within this dissertation identifies three major concerns in this relationship. Firstly, the issues related to the lack of research on the contingencies, secondly problems associated with the method of inquiry, and thirdly the conceptualisation of culture. Adopting these issues as a guide for further investigation, this dissertation investigates the black box of the TMT process through the use of both qualitative and quantitative methods/concepts, adopting national and ethnic diversity as proxies for cultural diversity. The majority of the studies in the group and TMT research indicate that cultural diversity is usually associated with negative group and organisational outcomes. The finding of this dissertation, however, indicate that TMT cultural diversity has a positive effect on organisational outcomes albeit under two conditions. Firstly, when TMT cultural diversity mirrors cultural diversity of the Board of Directors, indicating the importance of TMT interaction in the upper apex of the organisation, and secondly, when TMT has a shared vision that reduces the perceived negative influence of cultural diversity on TMT process and subsequently on organisational outcomes.