This paper examines the nature of multicultural project teams and their place in the global business environment. It highlights some of the issues regarding cultural complexity that exist in multicultural project teams and argues that, getting multicultural project teams to work effectively across international boundaries has become a major concern. The inclination is likely to continue and the future of business will increasingly depend on doing projects effectively in different cultural environments. This is difficult enough to achieve where the team is situated in the same office located close to the construction site. But it is much more difficult for multicultural global projects that have a range of diverse companies involved, are widely separated geographically and that have very different organisational and regional cultures. This study explored the efficacy of multicultural team working in heavy construction engineering in Kenya and the UK. The research employed both qualitative and quantitative methodologies to capture all the relevant experiences of senior managers. Using evidence from the two sets of participants, the study highlights some of the barriers to effective multicultural team working and demonstrates the critical importance of building cultural understanding through leadership. The findings revealed a number of determinants, attributes, and variables that either facilitated or limited the effectiveness of multicultural team working