Effective communication is an important element in improving employee performance in an organization. This research aims to examine the role of internal communication in improving employee performance at PT. Synergy Karya Abadi Kisamaun, Tangerang. This research uses a qualitative descriptive approach with a case study method. Data was collected through interviews, observation and documentation with superiors and employees of PT. Synergy Karya Abadi Kisamaun, Tangerang. This research uses the Neoclassical theory (Human Relations) put forward by Elton Mayo in 1927. The research results show that internal communication has a significant impact on employee performance. Research findings show that effective internal communication can increase employee motivation, job satisfaction and productivity. This research recommends that organizations prioritize internal communication to improve employee performance.