Nowadays, competition in the international contracting market is becoming increasingly fierce, and knowledge has become one of the most important resources for international construction projects (ICPs). Academia and industry have gradually realized that members’ individual knowledge should be integrated into the project work process by interacting with different individuals, which is defined as the process of project knowledge transfer. However, there is still a lack of concrete and complete understanding of how factors from each dimension (i.e., individual, team, and communication) integrate to affect knowledge transfer within ICPs. The purpose of this research is to examine the key drivers that affect knowledge transfer within ICPs from both individual and team perspectives. Data were collected from 353 samples of 87 international construction projects from people who were participating or had participated in the projects. The results of structure equation modeling (SEM) analysis suggested that cultural distance among project members hinders the willingness to transmit and receive knowledge, whereas members’ prior stock of knowledge positively influences their transmittal willingness. Then, intercultural competence and effective learning mechanism affect knowledge transfer effectiveness (KTE) by positively influencing internal communication intensity. Additionally, the degree of trust affects KTE by positively influencing members’ transmittal and reception willingness. Last, the willingness to transfer knowledge has a direct positive impact on KTE and also affects KTE by positively influencing internal communication intensity. This study provides suggestions for international project managers and members to promote KTE, which is conducive to the knowledge flow and accumulation of project teams and construction companies.