Sharing tacit knowledge is of great importance for an integrated project team to achieve success. However, research on the factors affecting tacit-knowledge sharing within an integrated project team has been insufficient in the construction management field. This paper aims to identify the critical factors affecting tacit-knowledge sharing and explore the interrelationships between these factors. Based on a literature review, the authors first identify 31 factors of tacit-knowledge sharing within integrated project teams. Through a questionnaire and statistical test, this research next analyzes the factors that are significant to tacit-knowledge sharing within an integrated project team. Then, factors analysis was used to study the critical factors of tacit-knowledge sharing. Finally, the authors analyze the interrelations among the critical factors and explore how they influence tacit-knowledge sharing within the integrated project team. The findings in this research demonstrate the impacts of trust on tacit-knowledge sharing with the evolution of trust taken into account. The authors also find that two personal factors are related to trust and tacit-knowledge sharing. This paper can provide useful guidance for an integrated project team to promote tacit-knowledge sharing and ultimately improve team performance. (C) 2015 American Society of Civil Engineers.