Purpose: The pressure on mass-housing construction to broaden performance from economic considerations to sustainability outcomes has increased significantly. Mass-housing projects in developing countries face challenges, including resource inefficiency, waste generation, and limited social acceptance. While knowledge management demonstrates positive effects on organizational sustainability, its systematic application in mass-housing construction remains largely unexplored. This study examines the impacts of knowledge management practices on sustainability performance across economic, environmental, and social dimensions. Design/methodology/approach: A structured questionnaire was administered to 185 construction professionals working on mass-housing projects in Tehran, Iran. Partial least squares structural equation modeling (PLS-SEM) was used to analyze the impacts of knowledge management strategies, capabilities, and sustainability performance dimensions. Findings: Knowledge management practices positively affect sustainability performance strongest for social, followed by environmental, with comparatively modest effects for economic outcomes. Social sustainability exhibits the most substantial association, followed by environmental outcomes; improvements in economic performance are positive but comparatively modest. Results suggest context-dependent effects, indicating a need for tailored implementation. Practical implications: Mass-housing developers must establish knowledge management frameworks addressing sustainability dimensions through tailored approaches. These projects require structured knowledge sharing that integrates technical standardization with community engagement to achieve enhanced outcomes. Originality/value: This research provide evidence of differential knowledge management effects across sustainability dimensions in mass-production housing, addressing a gap in construction management literature regarding organizational knowledge practices in developing economy contexts. Future Research Directions: Longitudinal studies, cross-cultural validation across developing countries, and AI integration in knowledge management systems for enhanced sustainability outcomes.