The nature of internal communication networks in project sales has remained largely unexplored. This article sheds light on a supplier's internal communication network during a project sales process by using social network analysis and in-depth qualitative data. We analyzed the project sales process and related internal communication network of a material handling equipment provider. The results illustrate the non-centralized and complex nature of internal communication networks and highlight four barriers to and four drivers of efficient communication during project sales. Above all, using communication training seems to be the most efficient way to improve internal communication.