This dissertation investigates the critical role of Belbin team roles and leadership styles in ensuring project success within the UK construction industry, focusing on the case of Carillion Company. The study explores the significance of project management, emphasizing the importance of effective leadership and team dynamics. It examines various leadership styles and the application of Belbin's theory in construction projects. The research utilizes a mixed-methods approach, including literature reviews, data collection, and analysis to understand how these factors contribute to project outcomes. Key areas of focus include the impact of clear communication, team roles, and leadership strategies on project completion, cost-effectiveness, and overall success. The findings highlight the importance of aligning individual and organizational goals, fostering open communication, and utilizing appropriate team roles to enhance project performance. The conclusion provides recommendations for improving project management practices in the construction industry, emphasizing the need for effective leadership and team role management.