The number of projects has increased immensely, as projects allow flexibility and can be widely applied. Even though that there has been an increase in the number of projects that are started, there is still a high number of projects that fail to meet the requirements. Project management has become an intensively researched topic, as it is an enabler for the enhancement of the success of projects. Effective communication has been identified as the most important factor contributing to the success of projects. Therefore this research aims to explore the effect of communication on project performance, with communication media as a critical aspect of cross-functional project teams, taking the contextual factors complexity and familiarity into account. The main research question that will be answered in this thesis is the following: What is the influence of communication media on the performance of cross-functional project teams? To answer this question, a thorough literature review has been conducted. The literature has served as the basis for the research. In order to determine whether a project can be deemed a success or a failure, a conceptualization of project performance was made based on the literature. This helped in assessing the performance of projects. Next, communication is dissected into two processes, conveyance, the process of exchanging new information, and convergence, the process of gaining a mutual understanding. For this research the contextual factors complexity and familiarity are taken into account. As information is exchanged, it is important to make a distinction of the information that is exchanged, as some information is complex and some is not complex. The complexity of information is a function of uncertainty and equivocality. Familiarity positively influences the relationship between communication and project performance as it enhances the quality of communication. With the basis known of communication, a dive was made into communication theories. The Media Richness Theory (MRT) was discussed, which discusses the richness of information and the ability of communication media to convey rich information. As an extension of this, the Media Synchronicity Theory (MST) was discussed, which explains the concept of synchronicity, and the ability of media to be synchronous. The last theory which was discussed is the Social Presence Theory (SPT), this theory explains the ability of media to express social presence. Social presence is an important aspect as it fosters trust and enhances the creation of relationships. Based on these three theories an analytical framework was created, that helps to create a media fit based on the characteristics of communication media and on contextual factors such as the complexity of the information exchanged and the familiarity. The analytical framework was used as the basis for the case analysis. The case analysis existed out of two sets of interviews with employees of the (Gas Mobility PRO) GMOB-PRO department of TotalEnergies and of an analysis of the Tanzania project, which is an advisory project. The interviews showed that there was a lack of structure at the GMOB-PRO department, this lack of structure resulted in working in silos, inadequate use of communication media, lack of trust within the department, and a lack of focus on projects that are not hydrogen related. In addition to this, a project was analyzed, the Tanzania project, the first advisory project. The results of the analysis clearly showed that email was the preferred communication medium, even when there is clarification is required. Next to this finding, clearly, the lack of focus on projects other than hydrogen was confirmed. By not using the proper communication media, the project was delayed as communication via email does not foster a rapid back-and-forth of information exchange. This resulted in an increase in cost as the quotations expired. To answer the main research question, communication has an indirect effect on project performance, as it can not directly influence project performance. Project performance is indirectly influenced by communication via aspects such as clarity and understanding, decision-making, team collaboration, resource allocation, and stakeholder engagement. If used properly, communication media enhances the effectiveness of communication, which indirectly affects project performance. Following the results of the literature, it is recommended for companies, such as TotalEnergies make use of clear structures for projects. Next to this, it is recommended to create awareness of the capabilities of communication media. By creating awareness of the communication processes, the characteristics of communication media, and the ability of communication media to convey information, individuals will be able to communicate more effectively, improve collaboration, and thereby increase the organization’s success. In addition to this, individuals can use the analytical framework as a tool to improve their communication efficiency.