This study examines improving the documentation and application of lessons learned in tender processes within the Dutch construction sector, focusing on Royal BAM Group. Despite the need for effective knowledge management, challenges like fragmented knowledge sharing and inconsistent documentation persist, limiting organizational learning. Using Social Network Analysis (SNA) and Root Cause Analysis (RCA), the research identifies key organizational, technological, and cultural barriers impacting knowledge sharing. The study proposes a GIS-based application to enhance access to lessons learned across departments. Recommendations include short-term actions and long-term strategies to formalize documentation and foster a learning culture, aiming to optimize future tender projects.